adding the mutex header file dependency
Implemented System.IO.Compression.FileSystem.
Merge pull request #1196 from tritao/master

System.IO.Compression.FileSystem implementation
Fixed Path.GetFullPath to work correctly when the current path is '/'.

Fixes xambug #833.
Merge pull request #1201 from crisdut/fix-win-mono-dependencies

Adding the mutex header file dependency
Implement some of 'not implemented' member functions