Remove dependency on MSVCRxx.dll for libadb

Link to the runtime statically
Merge pull request #745 from bkase/statically-link-mt

Remove dependency on MSVCRxx.dll for libadb
Simplified mutex-related code in Windows shutdown
Merge pull request #752 from bkase/mutex-simplification

Simplified mutex-related code in Windows shutdown routine r=@ochameau