Backport from ogl-es into the opengl driver: Use INCR_WRAP and DECR_WRAP when available even for the usual stencil algorithms, to avoid holes in the shadow.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@2392 dfc29bdd-3216-0410-991c-e03cc46cb475