Filter GetRelatedDocumentIds and GetLinkedDocumentIds by language to resolve NullReferenceExceptions in Salsa ContainedDocument scenarios

Merge master into future

Merge future-stabilization into future

Merge remote-tracking branch 'upstream/future-stabilization' into merge-future-stabilization-into-future20160415-150211

Unify NuGet dependencies across the tree

Delete the last remaining project.lock.json

These keep coming back.

To prevent projects across the tree from having different dependencies, we unify
external package dependencies by creating empty C# projects that represent them.
We then make use of project.json package inheritance (where a project inherits
all packages dependencies from their dependencies) to unify it across the tree.

No projects outside of this tree, should be directly referencing versions of
these dependencies manually.

For this check-in I've tackled Metadata, Reflection, and DiaSymReader. Will tackle
the rest in future commits.

some code clean up and made active and project state to be merged when a file is closed

Go to the start of the current member first.

- Making Project.Language check case sensitive

# Conflicts:
#	src/VisualStudio/Core/Def/Implementation/TableDataSource/VisualStudioBaseDiagnosticListTable.LiveTableDataSource.cs

Merge stabilization into master

Fix VS binding redirects

Merge master to stabilization

fixed build race

Merge master into future

tweak virtual memory monitor on full solution analysis

In turns out that the behavior of "Go to previous member" in VB was actually
to go to the start of the current member if you weren't already at the start.
Support that again.

Fixes #10588

Merge master into stabilization

Include System.IO.FileSystem in Roslyn.Build.Util package

Include System.IO.FileSystem in Roslyn.Build.Util package

will result in a linked doc language being “TypeScript” when the original
doc language was “C#”. This is because GetLinkedDocumentIds() and GetRelatedDocumentIds()
retrieve documents based on the file path and both of the ContainedDocuments will have
the same path (ex: LoginView.cshtml) with different documentIds.

This leads to NullReferenceExceptions in Salsa ContainedDocument scenarios

Fix:
- Change GetRelatedDocumentIds(DocumentId documentId) and GetLinkedDocumentIds() to filter documents by language
- Add GetDocumentGroupKey method to AbstractRoslynTableDataSource and use this instead of GetRelatedDocumentIds for the aggregated key

the race happened since we cleared _state before pending background work is all finished.

now we correctly capture state so that right state is passed around.

fixed build dedup bug caused by recent change.

Merge stabilization into future-stabilization

Merge stabilization into master

Add a regression test for binding local functions in incomplete code