several changes towards 5.3, XINERAMA is disabled by default, introduced usegrab...

several changes towards 5.3, XINERAMA is disabled by default, introduced usegrab Bool for grabbing the server during mouse-based resizals/movements (disabled by default), continued debugging tile() with resizehints == True and a lot of terminals supporting resizehints, still no optimal solution, I need to think about it, considering recursive algorithm for the space optimization