mpd: Make regexps work with re.VERBOSE
mpd: Remove redundant ^ from all patterns

re.match() only matches on the start of the line anyway.
mpd: Use same regexp flags everywhere
mpd: Reduce indentation of multiline regexps
mpd: Match just ' ', not any space char
mpd: Reformat query regexp
mpd: Move query_from_mpd_search_format into only module using it
mpd: Split out common query fields
mpd: Rename constants
mpd: Reformat list query pattern
mpd: Ensure quotes are matched
mpd: Sort search fields
mpd: Add note about use of re.VERBOSE
mpd: Remove redundant ^ anchor in example pattern
mpd: Register the two playlistid forms explicitly
mpd: Add TODOs for remaining quote matching
Merge pull request #584 from jodal/feature/mpd-regexp-improvements

MPD regexp improvements
zeroconf: Avahi doesn't support announcing on the loopback interface
dbus: Set GObject event loop as default DBus loop

This must be done early in the process life cycle to have any effect. In the
MPRIS frontend code is too late. Right before the GObject loop is created in
RootCommand.run() is also too late.

Fixes mopidy/mopidy-mpris#2
docs: Update changelog