Rotate window on linux

F11 rotate window (geometry) when "python app.py -m keybinding -m screen:droid2,portrait" on win, linux and macosx.
I can not do the tests on macosx and windows. But I don't touch any platform dependent features.

__Updated with commit cb3b635.__ I had commented (in 23/04/2013, 17h05 BRT):

I talked to @qua-non and came to the conclusion that I must refine the proposal for the new feature to use the keyboard shortcut __Shift+F11__. I am making it.