fix #636
Fix core unit tests
Use FullName as a key for project cache

Project.UniqueName is null or raises exceptions in some situations.
Project.FullName is much safer to use.

Fix #634.
Try to fix unit test timeout on AppVeyor
Put potentially timed-out tests into a separate category
Merge pull request #635 from dungpa/project-cache

Use Project.FullName as keys in project cache
Merge pull request #637 from bleis-tift/master

fix #636
Skip timer delay in order to do unit testing easier

This should fix intermittent test failure on AppVeyor CI.
Merge pull request #639 from dungpa/vs-tests

Skip timer delay in order to do unit testing easier
Don't manipulate symbols if unused declarations are disabled
Merge pull request #642 from dungpa/grayout-option

Don't manipulate symbols if unused declarations are disabled