(wx) Added redraw callback

Which windows (and possible mac) requires to get redrawing to work.
I can't believe I missed this.

Must test this at home on my old-slow XP machine.
(wx) event handling optimizations.

And fix keyboard events
 wx fixes hidden cursor, maxmize, get_mouse_state

get_mouse_state which returned the coordinates in screen coordinates.
Use wx fileselector on all OS'es
Add real native window menus
Convert dialogs from OpenGL to wx
Fix popup menues
Fix native statusbar and fix progressbar