Win32: typo fix in Pbuffer.c
Win32: Fix type in exception message in context.c
Win32: Handle context-dependent wgl extensions
Linux: Handle different GLX capabilities on different screens
Win32: Compile fix
Removed unsued JNIEnv parameter from extgl_QueryExtension
Linux: Fixed glx
Moved platform specific stuff from extgl.c into platform directories
Typo fix
Clean out commented code