made ObjectWriter/Reader to be able to write primitive type array

Merge dev15-preview-4 into master

Make sure to clear SymbolKeyReader.CurrentMethod before placing in pool 

Remove extra base

Clean up snapshot service naming

The invariant of SymbolKeyReader is this should be non-null only if
it's inside a call to MethodSymbolKey.Resolve. This is ensured by
guards inside that function. However, if we cancelled in the middle
we would end up reusing the type without it being set back to null.

Fixes #12790, as well as any memory leaks this would cause too.

Manage our project.json files programmatically

fixed race where field is set before write to temp storage is done.

Update DSRN to 1.5.0-beta1

Merge remote-tracking branch 'dotnet/dev15-preview-4' into merge-dev15-preview-4-into-master20160801-150058

Fix #12421 - Make CSharpSyntaxFactsService a singleton

Fix a couple of official build issues

Fixes

1. Fixes warning about neutral chip in the telemetry SWIX project.
2. Only build NuGet.proj once.  Previously built from Build.proj and SetupStep2.proj

Verify SWIX builds on Jenkins