Be tolerant of msbuild failures when opening project files to find output path for loading metadata instead of project sources.

Add skipped test for another repro case for #463

Closes #1700.

Cleaned up CA1821 (Remove empty finalizers) and fixed a bug in the fixer

Adding error triggers  for the add-usings fixers

Fixes #935
Fixes #562

Make C# snippet completion obey the "SendEnterThroughToEditor" option

Use the standard logic to determine whether to send enter through to the
editor, which requires using CSharpCompletionItems.

Fixes internal bug #1140893.

Include Project Name and FilePath in debugger display for ProjectInfo

Fixes #2159

[Localize] partially localize a part of strings like "finally clause"

We use resource commenting "locked" to define what to localize. It fixes #2215.

Add new analyzer assembly loaders.

Currently we expect that an analyzer's dependencies are located next to
it in the file system, and we do not require that those dependencies be
explicitly passed to the compiler. These requirements are changing. We
will now allow analyzers and their dependencies to be located anywhere,
and this requires that the full set of analyzers and dependencies be
passed in so that we know where to find them.

In order to load analyzers and dependencies under these new
requirements, this commit introduces two new analyzer loaders:

* The `SimpleAnalyzerAssemblyLoader` type loads assemblies from their
current location with a simple `Assembly.LoadFrom`. This is used in
situations where it is OK to lock the file on disk for the lifetime of the process
(e.g., in csc/vbc/csi/vbi) and as the default in the workspaces layer.
* The `ShadowCopyAnalyzerAssemblyLoader` first copies an assembly
and its resource files to a temporary location, and then loads it from there.
This keeps the original file unlocked, and is meant to be used by longer-
running processes (VS, vbcscompiler.exe).

Both implementations also hook the `AppDomain.AssemblyResolve` event in
order to find and load items from their list of dependencies.

**Work included in the current review:**

1. Defining a loader that loads in-place (`SimpleAnalyzerAssemblyLoader`).
2. Defining a loader that shadow-copies assemblies and loads them from
the new location (`ShadowCopyAnalyzerAssemblyLoader`).
3. Plumbing the loaders through csc/vbc/vbcscompiler/workspaces/VS.
4. Removing the old `InMemoryAssemblyProvider` entirely and updating
the code that previously depended on it for notification for when an
assembly was loaded.
5. Making the new loaders internal in order to minimize our public
surface area.

Adding additional errors for the Add Imports/Usings fixers to react to.
Now, when we get an error on an extension method we offer to import the
correct namespace.

Fixes #935
Fixes #562

Avoid duplicate generate method fixes in light bulb

Use the standard logic to determine whether to send enter through to the
editor, which requires using CSharpCompletionItems.

Fixes internal bug #1140893.

The fixer removed the squiggled node and for VB that would be a MethodStatementSyntax instead of a MethodBlockSyntax and the RemoveNode call fails. Fixing it by simply calling SyntaxGenerator.GetDeclartation before removing and that does thte right thing.

Fixes #2257

Fixes #1899

Consider the following case where M1 and M2 are non-existant methods -

this.M1(System.Exception.M2());

The code fix provider for generate method was offering two fixes to generate the method M1 above. Here's why. The fix provider gets called once each for the two diagnostics on the above line - the first with span corresponding to M1 and the second with span corresponding to M2. For the first span, the fix provider correctly constructs a fix to generate M1.

For the second span the fix provider correctly realizes that it can't construct a fix to generate M2 since System.Exception is a type from metadata and not source. However, looks like fix provider has fallback code to walk up the tree and see if there are other methods that it can construct in such cases. It ends up finding the InvocationExpression for M1 up the tree and therfore ends up returning another fix for generating M1.

I didn't want to change this fall back logic since it appears to be shared across multiple GFU fix providers and I didn't want to break other legit cases where this may be required for generate method.

Instead I am fixing this by introducing equivalence key for the corresponding CodeAction to ensure that the duplicate fixes will get filtered out when the light bulb presents the list of fixes in its UI. (This is identical to equivalence keys that we have in place for other GFU fixes such as Generate Type etc.). Note that we need the equivalence key for generate method anyways to avoid duplicate fixes in other unrelated cases such as following where M is a non-existant method -

var x = this; var y = this;
string.Format("{0}:{1}", x.M(), y.M())

Also, note that in some cases where we used to offer multiple valid fixes to generate methods with the same name but different signatures before, we will now only display one fix at a time. But this is fine since user can always fix first issue then invoke light bulb again to fix 2nd issue. Example of a case where there are 2 methods with same name but different signature -

this.M(this.M());

re-filter signature help providers if the file's content type has changed

We use resource commenting "locked" to define what to localize.

Cleaning up unused msbuild imports that was causing MSBuildWorkspace to fail

Add support for TypedConstant and TypeOf expressions

Remove use of ClearTrivia on SyntaxGenerator inputs

Re-enable the ResultProvider tests

Formatting Service should honor Smart Indent Option

...now that the CI machines have been updated.

Fixes #1178

Fix #2224 : Formatting Service should not format the whitespaces before
Braces if Smart Indentation Option is set to None

Cleaning up an unused msbuild import that was causing MSBuildWorkspace to fail. We don't have a Nuget.targets anymore

Options pages

Hide some confusing options and remove confusing words.

Use Microsoft.DiaSymReader.Native to make PDB id and stamp deterministic

Display a tooltip for hyperlinks in error list and preview pane

Display a tooltip containing url destination for hyperlinks in the error list and light bulb preview pane UIs.

Also use full fidelity (i.e. substituted)  error message in the search query in the case of hyperlinks that redirect to bing search so that we can present more relevant search results.

Fix an incorrect tautological if condition

Replace CreateStreamOnHGlobal with a custom COM Memory Stream