A change in the poll callback that Available KeyingSet used to use
restricted its use to Object-mode only, while this could also be
useful in Pose Mode (though it would only affect all channels there).
Made this use a custom poll callback now that tests for whether the
active object has an action. This does mean that if you select a bunch
of objects with animation data, but the active object doesn't have it,
then the keyingset will fail to fire, but that's been marked as a todo
in the code.
Rotation and Location don't have Keying Sets
Added Keying Sets for Delta Loc/Rot/Scale settings (aka dLoc/dRot).
These settings could already be found in the Object properties, under
the collapsed "Delta Transforms" panel.
I've added these to the end of the Keying Sets list, since adding any
earlier will end up breaking active Keying Set setting in older files.
Besides, these settings aren't that frequently used either...
ui/ --> startup/bl_ui
op/ --> startup/bl_operators
scripts/startup/ is now the only auto-loading script dir which gives some speedup for blender loading too.
~/.blender/2.56/scripts/startup works for auto-loading scripts too.
