This change makes SendKeys less flaky and removes the delay between characters, which was hiding bugs. Now, we just wait for application idle before blasting keys to the VS process. Additionally, I've started more cleanly separate code that runs in process vs. out of process.

This makes it more natural to set up tests where the editor is expected to have some code and the caret is expected to be positioned. This also removes some crusty DTE code that was executed over RPC.

This is the initial punch through that contains:

- A few more tests ported from CSharpAutomaticBraceCompleteion
- Tons of clean up (and more to come) in the SendKeys implementation
- Fix for incorrectly defined `VkKeyScan` Win32 API P/Invoke (needs to be unicode CharSet!)
- Fix code which tests text before and after caret
- Fix loads of bugs in the existing tests

Removing redundancies in conditionals and useless string.format

Cut short recursion that can occur (by spec!) in the better betterness code.

Fix build versioning variables and stamping

* Merge pull request #12041 from heejaechang/buildsyncrace

found one more case where documentId can be null

* prevent VS from crashing if VS got shutdown while build error reporting is in progress.

* Update our NuGet package version to 1.3.2

* Update Microsoft.DiaSymReader.Native to 1.4.0 RTM (#12141)

* Enable building of release nuget packages.

This commit makes it so that we will always try to generate release nugets except if they depend on prerelease packages. If one of our nuget packages happens to depend on prerelease packages, then when building release nugets, we will simply print a message in the build output and skip release nuget generation for that package (and allow the overall build to succeed).

* Address code review feedback.

* Simplify script to use nuget.exe for prerelease dependency validation instead of adding custom logic in the script for this.

* Remove Microsoft.CodeAnalysis.EditorFeatures from list of prerelease nuget packages.

* Change the name of the error log file to skipped_packages.txt.

* fixed DifferenceViewer leak

this leak was responsible for about 14% of managed memory in customer's dump.

basically, in certain condition, if cancellation exception is thrown, we will not close difference viewer which cause
all text views to leak. that cause all taggers and text buffers to leak and that cause our preview workspaces to alive.
which in turn cause all solutions to alive and so on. all those objects (view, buffer, workspace, solution) are quite
big graphs. so ends up eat up 14% of memory.

added assert to make sure if we leak viewers again, we get some kind of notification.

* Skipping the InteractiveWindow Clipboard UnitTests as they cannot run on VS2015.2

and calls outside the recursion call a version of the method that does not
have the recursion limit parameter. (As suggested by code review)

throw is not a possible expression

* Merge pull request #12041 from heejaechang/buildsyncrace

found one more case where documentId can be null

* prevent VS from crashing if VS got shutdown while build error reporting is in progress.

* Update our NuGet package version to 1.3.2

* Update Microsoft.DiaSymReader.Native to 1.4.0 RTM (#12141)

* Enable building of release nuget packages.

This commit makes it so that we will always try to generate release nugets except if they depend on prerelease packages. If one of our nuget packages happens to depend on prerelease packages, then when building release nugets, we will simply print a message in the build output and skip release nuget generation for that package (and allow the overall build to succeed).

* Address code review feedback.

* Simplify script to use nuget.exe for prerelease dependency validation instead of adding custom logic in the script for this.

* Remove Microsoft.CodeAnalysis.EditorFeatures from list of prerelease nuget packages.

* Change the name of the error log file to skipped_packages.txt.

* fixed DifferenceViewer leak

this leak was responsible for about 14% of managed memory in customer's dump.

basically, in certain condition, if cancellation exception is thrown, we will not close difference viewer which cause
all text views to leak. that cause all taggers and text buffers to leak and that cause our preview workspaces to alive.
which in turn cause all solutions to alive and so on. all those objects (view, buffer, workspace, solution) are quite
big graphs. so ends up eat up 14% of memory.

added assert to make sure if we leak viewers again, we get some kind of notification.

* Skipping the InteractiveWindow Clipboard UnitTests as they cannot run on VS2015.2

* Merge pull request #12041 from heejaechang/buildsyncrace

found one more case where documentId can be null

* prevent VS from crashing if VS got shutdown while build error reporting is in progress.

* Update our NuGet package version to 1.3.2

* Update Microsoft.DiaSymReader.Native to 1.4.0 RTM (#12141)

* Enable building of release nuget packages.

This commit makes it so that we will always try to generate release nugets except if they depend on prerelease packages. If one of our nuget packages happens to depend on prerelease packages, then when building release nugets, we will simply print a message in the build output and skip release nuget generation for that package (and allow the overall build to succeed).

* Address code review feedback.

* Simplify script to use nuget.exe for prerelease dependency validation instead of adding custom logic in the script for this.

* Remove Microsoft.CodeAnalysis.EditorFeatures from list of prerelease nuget packages.

* Change the name of the error log file to skipped_packages.txt.

* fixed DifferenceViewer leak

this leak was responsible for about 14% of managed memory in customer's dump.

basically, in certain condition, if cancellation exception is thrown, we will not close difference viewer which cause
all text views to leak. that cause all taggers and text buffers to leak and that cause our preview workspaces to alive.
which in turn cause all solutions to alive and so on. all those objects (view, buffer, workspace, solution) are quite
big graphs. so ends up eat up 14% of memory.

added assert to make sure if we leak viewers again, we get some kind of notification.

* Skipping the InteractiveWindow Clipboard UnitTests as they cannot run on VS2015.2

This was causing infinite loop for code like "F(throw".

This handles the simplest cases that are likely to arise in practice. We simply limit
direct recursion in "better conversion target" to a depth of 100.
See #12061 for the related spec bug. The spec still must be adjusted to say what should happen here,
and the implementation will need to be changed to follow that new specification.

- Introduce a new variable, RoslynFileVersionBase, which specifies the
  file version base we will use. This controls the file version as
  stamped in the PE, and also the version that's used for our NuGet
  packages.
- Rename RoslynSemanticVersion to RoslynAssemblyVersionBase so it's
  more clear what that's used for.
- Ensure that the PE file version header changes for each day, to give
  some protection that build-to-build upgrade correctly works for
  MSI-based installs, and also for sanity so you can have some hope
  when looking at a binary on disk.

We haven't used this for ages, and is most likely terribly broken.

* Merge pull request #12041 from heejaechang/buildsyncrace

found one more case where documentId can be null

* prevent VS from crashing if VS got shutdown while build error reporting is in progress.

* Update our NuGet package version to 1.3.2

* Update Microsoft.DiaSymReader.Native to 1.4.0 RTM (#12141)

* Enable building of release nuget packages.

This commit makes it so that we will always try to generate release nugets except if they depend on prerelease packages. If one of our nuget packages happens to depend on prerelease packages, then when building release nugets, we will simply print a message in the build output and skip release nuget generation for that package (and allow the overall build to succeed).

* Address code review feedback.

* Simplify script to use nuget.exe for prerelease dependency validation instead of adding custom logic in the script for this.

* Remove Microsoft.CodeAnalysis.EditorFeatures from list of prerelease nuget packages.

* Change the name of the error log file to skipped_packages.txt.

* fixed DifferenceViewer leak

this leak was responsible for about 14% of managed memory in customer's dump.

basically, in certain condition, if cancellation exception is thrown, we will not close difference viewer which cause
all text views to leak. that cause all taggers and text buffers to leak and that cause our preview workspaces to alive.
which in turn cause all solutions to alive and so on. all those objects (view, buffer, workspace, solution) are quite
big graphs. so ends up eat up 14% of memory.

added assert to make sure if we leak viewers again, we get some kind of notification.