Force Mono.Cairo remap.
Update windows gtk# installation.
Don't let xcopy prompt for overwrite confirmation.
Use monodoc.dll from dependencies, drop stale MonoLibraries installer.
Revert "Use monodoc.dll from dependencies, drop stale MonoLibraries installer."

This reverts commit 8f22011e332535be69394bf0ca9416ea44b9cd11.
Overwrite old monodoc.dll.