Blender Git Loki

Fix T38619: Confusing logic for Keying Set keyframing Settings

The logic used for determining whether certain keyframing settings (i.e. visual,
only needed, xyz -> rgb) got applied was wonky. The original intention here was
that the Keying Set settings would override the global settings, and the path
settings would override what was used for the Keying Set. However, that was not
happening in all cases previously, as it was only possible to add flags and not
to turn them off.

This commit fixes that by introducing separate toggles to control whether the
Keying Set/Path's settings override the settings inherited from its parent
(i.e. the Keying Set for the Path, and the User Prefs for the Keying Set).
The icons used for these toggles could get revised a bit (we need something
which communicates "override this"; the current one is the closest I could find)

WARNING: If you have old keying sets, this may cause some breakage!