Daemon: Bugfix for layer ordering

We never actually sorted the layers because the sorting
function we called didn't sort in-place but returned a new
container, which we discarded. Oops.
Daemon: add web server

It offers a simple API that can currently be used
to control a global dimmer and a backlight.
It will always listen on 0.0.0.0:8080
Daemon: make server interface/port configurable