* replaced the alsa output device detection and selection mechanisms with those from https://github.com/ronalde/mpd-configure/blob/master/tests/detect-alsa-output-capabilities.sh. This makes it possible for the user to choose a device when multiple devices are available.
* added a LIMIT filter to limit the available output devices, in addition to the PREFERRED filter which still works
* incorperated the contents of the mpdconfigure-* files in to the main script, which were sourced in earlier versions
* removed the volume control functions because they didn't work properly (only tested on my own system), and are not in the right place (no possibility for 'offline' use)