Another poke at matrix4::transformPlane(). Tested with the example from the report, a (1,5,1) scaled node in 02.Quake3Map, and the existing regression tests, with some expected results updated.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@1970 dfc29bdd-3216-0410-991c-e03cc46cb475