When using -g hint the WM that we've got user specified geometry

Without this some window managers (e.g. fvwm) will ignore the initial
window position and place it according to it's own rules.
Merge remote-tracking branch '4z3/set-user-specified-sizehints' into sizehints

Conflicts:
	window.c
Refined US{Position,Size} & WinGravity handling
No checks on window size, use whatever the user has specified
Merge branch 'sizehints', fixed issue #78