Blender Git Loki

Fix for bug #1756

This was caused by a very primitive method of interpolating quaternions.
It was converting quats to mat and back to quat, and then just doing
a linear interpolation. That whilst quaternions are renowned for having
good interpolation possible.

I've experimented with 2 quaternion interpolation methods, and can only
get one to work correctly... the "official" version from Watt brothers
I can't get working, both are in arithb.c now.

Will arrange *close* review with experienced NLAers for it! But testing
here gives fully predictable results.

Also changed;
- added pointer check in drawaction
- changed puldown menu for correct hotkeys for move NLA strips up/down