Make sure clients only connect to signals once

This means a huge speedup when you do silly things like make a client
fullscreen and not fullscreen fifty times.
Kill forcedFloating with fire.

This is completely unnecessary.
Try to auto-adjust when struts change
Introduce more error checking

It's better to be notified when something goes wrong than for it to be
ignored silently.
Readd some moveStep stuff

Turns out it really _was_ needed.
v1.1.1

- Bugfixes