https://sourceforge.net/tracker2/?func=detail&aid=1339139&group_id=74339&atid=540679

This is a very small API breaking change to a method that's unlikely to be heavily used in user code. It is commented in the declaration, in changes.txt and a unit test has been added.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@1958 dfc29bdd-3216-0410-991c-e03cc46cb475