Removing all win32 mutexes and turning them into critical
sections, since mutexes in win32 are meant generally for
inter process communication, tend to be slower, and aren't
really needed for current purposes. Critical sections
are roughly equivalent to std::mutex in the c++ stl.
Certain applications using the Voodoo adapter stop blitting
when there's no activity (e.g mouse movement, animation).
This results in a black screen when events like window/full screen
transitions take place. Usually this can be fixed by
moving the mouse or with keyboard inout. This change forces
a blit to refresh the screen.
In addition, added critical sections since they are lighter
than mutexes.
