Read test projects from external project files
Support multiple projects in VS unit tests
Add missing functionalities to ProjectParser
Make sure test projects are built before testing

Fix #640.
Skip the failing test on CI
Merge pull request #687 from dungpa/vs-tests

Support multiple projects in VS unit tests
Don't gray out override members

Close #622.

FCS never returns more than one symbol for override members. We skip
these in checking unused symbols for now.
Merge pull request #689 from dungpa/interface-properties

Don't gray out override members