Hello everyone,

I hacked some more event handling into the W32 version of GRX:

- GR_SIZE_CHANGED: Tell the program that the size of the GRX window was changed from outside

- GR_OS_DRAW_REQUEST: Let the program know that the OS wants the program to redraw its window. (Normally, GRX handles this in the background, but if you use non-GRX output such as OpenGL in parallel, this can be useful.)

- GR_COMMAND: Events that come from, e.g., a menu rather than the keyboard or mouse directly

Patch attached.

Have fun,

Peter