Blender Git Loki

- pulldowns and 'BLOCK' buttons now open automatic, when mouseover
without moving for 0.25 second. Also works for sublevels in pulldowns.
- removed hacks from mainloop, which caused setting the main window and
active subwindow for each event (including mousemove).
WARN: test for all OS's that no events get lost, and active window focus
is OK. For OSX it works nicely
- reduced load for uibuttons with 50%....