Returns currently used color - depending on state and if override color is set.
Note: Not adding this to editbox for now as it's a bit more tricky there (selection changing color, so it has no single color).
git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@6165 dfc29bdd-3216-0410-991c-e03cc46cb475