Blender Git Loki

Armature: Change Bone drawing.

This makes a few changes:
- Remove the old "overlay" wires.
- Add constraints colors to bones.
- Specify a a new "hint" color per bone. Making selection/Active state
more obvious.
- Unify Octahedral/B-Bones/Envelope shading and colors.
- Change outline size depending on the selection/active state of the bone.

Note that thoses changes are not final and needs review.