* Implement source link feature

* Fix CommonCompiler to open source link stream, add E2E tests

* Reduce code duplication across VB and C#

Merge dev15 preview 4 into master20160804 225700

Move type to file: offer outer.inner.cs pattern on nested types

Change hard coded xunit reference to use MSBuild prop

In Rename File to match type name scenario, the file rename is performed
by a remove followed by a add new. This causes the file to be closed and
reopened. But simply re-opening is not sufficient, we should make it be
the active document, because it was the active document before the
refactoring started. Without this, the file is opened in the background
and that switches away the user's context from the file they were
actively editing.

.. to move or to rename to.

In case of nested types, the accepted style of naming the file is either
by the standalone typename or with a dotted name derived from its type
hierarchy. For e.g: If type B is nested inside type A, acceptable file
names for type B is B.cs or A.B.cs

Offer these as suggested filenames if the file is named something other
than either of these two. These suggestions are then picked up and
surfaced as "Move to.." or "Rename file to.. " code actions.

Unify package versions

* Report non-fatal watson instead of crashing VS for failure to UnadviseFileChange in FileChangeTracker.StopFileChangeListening

Fixes https://github.com/dotnet/roslyn/issues/12819

* Address PR feedback and still crash on non-zero return code

* Add VSO bug number as comment for the workaround

Revert OOP work from preview 4

Move type to file: allow syncing filename and type name if no type in file matches filename

there is more than one type declaration and none of them match the
filename.

Merge dev15 preview 4 into master20160804 204800

This reverts commit 720f5c5e, reversing
changes made to 6a6043c3.

This reverts commit 90f48150, reversing
changes made to 720f5c5e.

Merge remote-tracking branch 'upstream/dev15-preview-4' into merge-dev15-preview-4-into-master20160804-204800

to include /nodereuse:false

Merge dev15-preview-4 into master

Merge commit '90f48150' into merge-dev15-preview-4-into-master20160804-150113

Update paths to new dependencies folders

crash right away when we don't get mandatory analyzers from VS.

made service hub works with dev15 preview 4 setup

Revert PRs #12725, #12726, #12786, and #12794 from `dev15-preview-4`.

made service hub works with dev15 preview 4 setup

added abstraction in remote host and diagnostic service to prevent VS…

Remove many of the dependency projects

List all available debug types in an error message

added abstraction in remote host and diagnostic service to prevent VS.Next dll from loading if remote host option is off.

the abstraction I added here is specific to diagnostic service feature. that abstract solely exist to prevent VS.Next dll from loading if remote host option is off.

this is different than IHostSpecificService abstraction I used to have that is generalized form of this abstraction which automatically figure out what to load based on option and layering/MEF composition of roslyn.

in this model, each feature need to take care of this kind of issue.

Introduce a "Latest" language version, which maps to the latest