Blender Git Loki

COLLADA importer: basic armature import.

Since in DAE only a matrix is stored per bone, some tricks have to be applied to build an armature from it:
- direction for "leaf" bones is hard-coded to Y vector. This will be changed to bone matrix orientation, somehow code will need to
derive the bone "forward" axis
- for "leaf" bones length cannot be determined, currently it is hard-coded (second screenshot), but I think changing it to the average
length of all non-leaf bones is ok
- parent bones get their tail at last child's head, this is not good (first screenshot). For bones with more than one child Chingiz
suggested not to link it with any child, I think it's a good idea. Length will be the same as for leaf bones.

Screenshots:
http://img232.imageshack.us/img232/8905/screenfhy.png
http://img406.imageshack.us/img406/3004/tobaggan.png