Blender Git Loki

More pose armature code factorization:
* New armature_mat_bone_to_pose, which is just the reverse of armature_mat_pose_to_bone (currently used by armature evaluation code only, but might be used by constraints space conversion code too, see note below).
* Found another place where another (a bit erroneous) pose_to_bone code existed (apply_targetless_ik(), in transform_conversion.c, used by "auto ik" option), replaced it by a call to armature_mat_pose_to_bone.

Notes:
* All those changes leave many #if 0 commented code, I will remove those in a few weeks.
* There is at least one other place where generic armature_mat_(pose_to_bone/bone_to_pose) functions should be usable: the space conversion function of constraints (constraint_mat_convertspace(), in BKE's constraint.c), but here I have some problems (old code is also somewhat erroneous, but using new one makes old rigs using bone space constraints wrong, e.g. sintel one, and it�??s just impossible to make conversion code...). So I'll wait and investigate more for this one.