Support move & resize with s-mouse-{1,3}

I really like this way to move window around in awesome. Hold the super key then use mouse button-1 on any window to move it, button-3 to resize it.
It looks like this diff is due to whitespace changes, can you format it so that whitespace is preserved and only functional differences are shown?  Please refer to https://github.com/stumpwm/stumpwm#contributing