house keeping
rewritten to fix a problem watching the stream
rewritten to minimize user interaction and handling of pulseaudio.
Cleaned up a bit according to http://mywiki.wooledge.org/BashGuide/Practices
* 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)
reflected changes in commit:cb6d162ca4d48222b48c77414076f56ccb8062ae
Bugfixes:

* added SCRIPT_DIR: needed when script is called from another
  directory
* added ALSA_OUTPUT_DISPLAY: fixes the display of card details in case
  there's only one or USER_PROMPTS is set.
Small fix

* added MPD_MUSICDIR: fixes the case when there's no XDG dirs and no
  music dir specified
Documentation fix

* removed and changed non existing example variables
* changed paths to Debian defaults
* added example of using a command (`HOSTNAME="$(hostname)"`)
Small fixes

* check if the preferences file (`mpd-configure.conf`) is present
  before trying to source it
* simpler messages when done
added latest commits
added sample to .gitignore
added tests/samples/cat-stevens-wild-world-hdtracks-24-192.wav to .gitignore
added tests/samples/cat-stevens-wild-world-hdtracks-24-96.wav to .gitignore
added tests/samples/cat-stevens-wild-world-hdtracks-32-96.wav to .gitignore