Blender Git Loki

Changed the default hotkeys for playing animations to be more useful IMO (ported from AnimSys branch):
* Alt-A now only plays the animation in the active space, if that space is a 3D-view. Otherwise, it plays the animation in all spaces. The old behaviour simply didn't make sense for animation editors, where you'd simply see the current-frame marker moving...

* Alt-Shift-A now plays the animation in all spaces regardless of whether they are active (including 3d-views)