A variety of operators were missing appropriate bl_options for correct
undo support.
This results in either crashes (auto loft, bi-rail) or other odd
behaviors around returning the scene to the correct previous state
(sometimes having to hit ctrl-z twice to undo once, sometimes undo skips
steps, etc.)
Differential Revision: https://developer.blender.org/D13283
This is a followup patch for D9697 which applies the changes to the
addon reporistory. Almost all of the changes are in rigify, but there
is one change in "curve_tools" and two trivial changes in IO addons.
Differential Revision: https://developer.blender.org/D9919
