Added a close event for windows (and in future other elements), absorbing this event will prevent the window from closing.
Used the new skin icon in the gui editor's resize button.
git-svn-id: http://svn.code.sf.net/p/irrlicht/code/trunk@879 dfc29bdd-3216-0410-991c-e03cc46cb475
Added IGUIElement::isMyChild, isPointInside, SEvent.GUIEvent.Element.
Changed setFocus and removeFocus to return bools.
changed quaternion::toAngleAxis to use iszero.
git-svn-id: http://svn.code.sf.net/p/irrlicht/code/trunk@763 dfc29bdd-3216-0410-991c-e03cc46cb475