Blender Git Loki

At last! B-bones now deform. :)
This works pretty nice for better control over the curvature of any bone
deform. No need to give Bones (vgroups) large influence, just add a coupleof B-bone segments.

Two notes;
- The Bone property "Segments" defines if a deform happens as a 'B-bone'.
The drawtype B-bone is just for display in 3d window.
- A B-bone also deforms (bends) in Rest-position, if there's a joint that
creates a curved Bone. Therefore, best results you get by creating a
rest-position with straight joints. Or, if you prefer a slightly bended
restposition (for a spine or so), make sure the Mesh model is *not*
curved, the B-bone will do this for you.

Also added: proper events on changing buttons for Bones, like "Segm" or
"Dist" etc.