Don't let overlays lose focus

if you open a new window while an overlay is mapped, the overlay should
stay focused

fix restoring pointer focus

I don't know why I thought it was working before. Maybe I should go do
something else.

improve code style

remove comment

I don't know why it wasn't working before but now it does ¯\(ツ)/¯
(it wasn't caused by the just removed code either)

remove mysterious code

Why would a surface that's not keyboard interactive get focused? Let's
remove this for now and see if issues arise.

focus the previous client in the similar code too

refocus old client

When a layer surface is destroyed focus should be returned to the last
client. Luckily if there are multiple overlays the previous overlay
still gets focused.

fix alhpabetical order

simplify focus leave condition

reuse motionnotify()

enable pointer on layer surfaces

more TODOs

fix focus leave condition

needs refactoring and testing

send pressed keys to topmost layer surface

update README

remove blank line

don't handle failed calloc

be consistent with the rest of the code

order variables more how like they are initialized

simplify make clean

Reuse render() and struct timespec *now