Moved .up() and .down() methods from Constraint API to Constraint sequence
API (also renamed them to moveUp() and moveDown() ). Again, methods which
modify the "parent" structure didn't seem consistent.
* use CONSTRAINT_LOCAL instead of SELECT in "Copy Rotate" constraint
* remove "LOCAL" key for now from "Copy Size" constraint; not supported
right now in Blender UI
Added NULL constraint (and fixed bug that didn't allow appending FLOOR
constraint), and added support for Constraint.Settings.LOCAL key support in
COPYLOC, COPYROT and COPYSIZE constraints when target object is an armature.
New Constraint API. Constraints are accessible through a "constraints"
attribute in poses and objects. Would be REALLY NICE for armature users to
pound on this code.