mpd: playlist name disambiguation
mpd: fix style issues and type errors introduced in 87ce309
Tests are now OK
mpd: minor style commit
mpd: bugfix in MpdContext.create_unique_name
mpd: added a test to check playlists names uniqueness
mpd: 'private' fields start with an _
Revert "mpd: 'private' fields start with an _"

This reverts commit f2000d6e6df362fa9c07379a483d91cf2b67ce88.

I did not have the code fresh in mind when saying that these should be prefixed
with _. As they are accessed from other classes, they are indeed public, and
should not be prefixed. My bad.
mpd: Fix flake8 warnings
mpd: Start numbering of duplicate playlist names at 2
Merge branch 'develop' into pr/396

Conflicts:
	mopidy/frontends/mpd/dispatcher.py
Merge pull request #396 from trefis/develop
Update changelog
mpris: Only import 'indicate' if $DISPLAY is set

This avoids printing of the following error message:

    ImportError: could not import gtk.gdk

Fixes #311
mpris: Disable extension if no $DISPLAY set

We cannot connect to the D-Bus session bus if there is no X11 $DISPLAY
available.
Merge pull request #407 from jodal/feature/mpris-needs-display

Turn off MPRIS if no $DISPLAY available
ext: Move ext helper functions from 'main' to 'ext'
log: Remove system info available in --list-deps
docs: Add empty troubleshooting page
docs: Rename 'changes' to 'changelog'
docs: Reorganize frontpage sections