fbo refactored
initial texture refactoring

Signed-off-by: serengeor <serengeor@gmail.com>
refactoring here and there.
Merge branch 'fbo' into development
GUI elements are renderable and somewhat work. Need to investigate parenting.
Font Rendering - initial stage.
Further polishing.
GUI Element dragging test.
REBASE. Rect2D clipping for GUI elements added. Dragging is fully functional.
Conflict fixing.