To do so, matching BKE 'API' was also refactored a bit: * Get Pose data instead of Object, as parameter; * Removed some sanity checks not needed at such a low level (callers are supposed to do that); * You can now remove an arbitrary bone group, not only the active one. Based on patch by pkrime (Paolo Acampora), with own edits. Reviewers: #python, pkrime, aligorith Reviewed By: aligorith Differential Revision: https://developer.blender.org/D522