swaybar: use select instead of busyloop
swaybar: use select instead of busyloop

Use of busyloop caused high cpu usage for sway because swaybar had to be
redrawn all the time. By using select instead the bar only has to be
redrawn when the status_command changes (i.e. every second) or when the
workspaces are updated.

Fix #345

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