Merge stabilization into master - 1

Merge remote-tracking branch 'upstream/stabilization' into merge-stabilization-into-master20160309-160047

Merge stabilization into master

Correct build order dependency for VB result provider

Fixed race in diagnostic tagger

This project uses the VB syntax generator hence needs a reference to the project in order to guarantee it's built first.

closes #7869

Turn off hard-linking during the build

We turned on hard-linking to reduce copy and build time, however,
this would result in behavior where copying a NuGet binary from .nuget/packages to the output directly which was then subsequently overwritten with a different version would result in the .nuget\packages folder to be corrupted because they were now linked.

Move to RC toolset

more allocation reduction.

This reverts commit b03e8478.

This changes the toolset we use to build Roslyn on our developer boxes to 1.2.0-rc.  Very close to release, need to make sure we're eating the latest brand of dogfood 😄

Merge stabilization into master

Non-Fatal Watson if ReiteratedVersionNumber matches when text does not.

Only collect archives in the case of aborted or failed runs.

Update what we archive after a run.

change telemetry reporting for rename

Only log formatting events in telemetry when they are enacted by the …

Fix crash if client completes the event queue before the compiler is finished with it.

Allow null Compilation in SymbolDistinguisher.Description.GetHashCode

Disable diagnostic service for projects that we know we don't have all information to provide good results.

Fix for 7845: add DynamicAttribute to event with dynamic type

Revert "Revert "Disable diagnostic service for projects that we know we don't have all information to provide good results.""

Port analyzer allocation fixes from master to stabilization

Fix race condition when generating simulated compilation events

Include HasValue check in BoundSwitchStatement

If the switch expression is a  Nullable<T>  a conditional branch is added for the  HasValue  check.
 That check was added as a separate  BoundStatement  outside of the  BoundSwitchStatement .
 If the lambda rewriter subsequently generated any display class instances, the allocations are added
 as a prologue to the rewritten switch statement but since the conditional branch is outside the switch
 statement, the branch skips the prologue, skipping the allocations. The change is to include the
 conditional branch in the  BoundSwitchStatement  so the branch occurs after the prologue.

[AskMode] Put `IOperation` behind a feature flag

don't assume all reference spans in an inline rename session are projected into the current view

Check file checksums to ensure no corruption occurred.

Add member visibility modifiers

- avoid instantiating nullable type when doing operator overloading on enums
- avoid instantiating generics when checking for impossibly rare case of duplicated interface implementations
- skipping materializing of sequence point array

Fix for #7809: check for use-site errors on attribute before synthesizing

Include HasValue check in BoundSwitchStatement so any display class allocation is moved outside of the check

No functional change here.