Blender Git Loki

Three fixes;

- On file reading, a check is added to see if a Pose has channels to
missing bones. Poses are supposed to match an Armature completely.
(Thanks for crash file, Johnny!... but how did you do it!)

- Own collection: added depsgraph update on setting all layers (with the
ACCENTGRAVEKEY). This also could potentially crash with modifiers

- Renamed Xkey menu in NLA to more properly tell what it does. :)