Merge current microupdate fixes back into master

fixed 2 memory leaks

Only compute entry points when compiling everything.

Add test to ensure that a CompletionService can be acquired

Issue #11841 found that, due to a MEF bug, the Features assemblies could not properly be included in a MEF composition. This was worked around by combining [ExtensionOrder] attributes where multiple attributes had been specified. This change adds a tests for C# and VB to ensure that a CompletionService can be acquired from an AdhocWorkspace that is created with MefHostServices that include the Features assemblies.

I verified that these tests fail without the workaound described above, and pass with the workaround in place.

MEF has issues with duplicate attributes.

Workaround for issue #11841 until MEF fix gets pushed to nuget.

Fixes #12113

Merge 'outvar' to 'master'

Unify snippet infrastructure between C# and VB

Update CoreFX to RTM, CoreCLR to the latest, SRM to v1.4.1-beta-24223-07

Merge 'master' to 'outvar'.

Use nuget.exe 3.5.0.1484

Use nuget.exe 3.5.0.1484

Merge future-stabilization into master

first one is preview workspace leak due to diagnostic service hold onto workspace.
second is capturing project in diagnostic exception handler

Generate the binding redirects for the compiler automatically

Generate list of packages for nuget.org

Remove workaround for lack of #7812

This removes the hard-coded binding redirects that exist within our
source tree in favor of redirects that are computed automatically. This
takes advantage of the built-in binding redirect generation support
in MSBuild. In order to get the redirects to merge properly with
the static stuff we have, I renamed the .exe.config files to App.config
which is the name the tooling looks for.

Addresses #7612.

Adjust various places outside of compiler to account for the fact that ArgumentSyntax.Expression can be null.

Adjust implementation of SyntaxTreeExtensions.IsLocalVariableDeclarationContext around Out Variable Declarations.

Don't simplify namespaces we add imports for.

Revert "Update CoreFX to RTM, CoreCLR to the latest bits, SRM to the latest"