added mute/unmute on long press

doesn't check alsa state if volume is changed outside of the program.
doesn't actually do anything via alsa at all, which it really should.
added syscalls `back` & `next` on press-and-twist
added bash scripts supporting mpd & pianobar
standardized script names
added manual page for rotomatic
removed pulseled source files
added udev rule to assign powermates to group input