BGE: Cleaning up BL_ShapeDeformer's use of Blender's Key. This also fixes a bug with replicas (added objects) crashing when using shape keys.

git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@56050 954f8c5b-7b00-dc11-b283-0030488c597c