Improve speed for finalizing skinned meshes (removal of unnecessary frames after loading) (thx @ichtyander for the testmodel)
Down from ~20 seconds to ~0,5 seconds :-)


git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@4622 dfc29bdd-3216-0410-991c-e03cc46cb475