Blender Git Loki

Quick Animation Feature: Paste Pose "Selection Mask" option

After discussions with ZanQdo, it was agreed that the current workflow
for making a pose symmetrical was a bit too cumbersome, especially
when auto-keying was enabled, requiring pasting the flipped pose on
another frame so that the changes could be merged back in without
overwriting the "good" half of the rig.

This option for the Paste Pose operator makes things easier, by adding
an option which will make the pose only get pasted on to selected
bones instead of overriding the entire pose. By default this option is
turned off, but can be easily enabled either from the toolbar
(operator properties) or through the F6 popup.

The intended workflow with this option for making a rig symmetrical is
now:
1) Copy pose
2) Select "bad" bones
3) Paste Flipped
4) Enable "On Selected Only" for the operator

If there is sufficient interest, this option can even be enabled by
default. But, we'll see about that later