- line2d::getMiddle and line3d::getMiddle work now also with integers. But can be slower in debug and for compilers which are not optimizing division by 2 to multiplication by 0.5 for floats also in release (if that still matters we need a template specialization here).

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@4070 dfc29bdd-3216-0410-991c-e03cc46cb475