Initial commit of Separate tool for Armatures. Currently, the functionality is hidden behind a temporary patch, as there are still issues to be worked out (crashes under certain conditions and a re-linking issue). It may remain like this for the release if I can't get it to work correctly.
Note:
- Hotkey for separate is Ctrl-Shift-P (it's a bit clumsy, and isn't consistent with P for separate for meshes, but Select Parent(s) is better as P)
5b73d96fd5