Prevent changing layout when focusing float window
Prevent changing layout when focusing float window

The layout command should only work with titled windows, thus it should
have no effect when a floating window has focus.

Should fix #643

ptMuta/sway,sleep-walker/sway,mikkeloscar/sway,ascent12/sway,1ace/sway,4e554c4c/sway,ascent12/sway,mikkeloscar/sway,1ace/sway,taiyu-len/sway,taiyu-len/sway,4e554c4c/sway,sleep-walker/sway,taiyu-len/sway,johalun/sway,ascent12/sway,1ace/sway,SirCmpwn/sway