add RNA_def_struct_ptr(...) to use for runtime struct registration, saves over 2000 string lookups on startup and gives overall ~10% speedup for starting blender on my system.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@53674 954f8c5b-7b00-dc11-b283-0030488c597c