Blender Git Loki

Animation: enforce that the active keyframe is always selected

Check selection state in `BKE_fcurve_active_keyframe_index()`, and only
return the active keyframe index when that keyframe is actually selected.
This is now also asserted in the `BKE_fcurve_active_keyframe_set()` function,
which is now also used when inserting a keyframe.