Add View Variables plugin
Handle pre/post #261
Remove unneeded import of track.
Show variables for tracks without files
PICARD-575: load plugins from contrib/ too when run from source directory

http://tickets.musicbrainz.org/browse/PICARD-575
Show multi-value variables as lists.
Fix display of multi-value for id3v23
addrelease.py: Refactor AddClusterAsRelease.

Abstract out some of the functionality all clumped together in
AddClusterAsRelease.callback() to methods of new parent class
AddObjectAsEntity.
addrelease.py: Abstract .callback() to parent class.

Child classes now just need to define object type, NAME, and the
set_form_values() method - and reigster_*_action.
addrelease.py: Abstract out submission URL.
addrelease.py: Add AddFileAsRecording class.

Allows for easily adding individual files as standalone recordings.
addrelease.py: Add AddFileAsRelease class.

Allows for easily adding single files (which can't be clustered) as releases.
addrelease.py: Update plugin metadata.

- Add Freso to PLUGIN_AUTHOR
- Update PLUGIN_NAME and _DESCRIPTION to describe added file
  functionality.
- Increment PLUGIN_VERSION to 0.5.
addrelease.py: Improve PEP8 compliance (E701).

Fixing instance of error E701: multiple statements on one line (colon).
Add Album Artist Website plugin - see PICARD-26

Adds a plugin to get the artist homepage MB relationship and insert into
website (ID3 WOAR tag).

Note: I used this plugin as a trial for using a Picard xml module to
handle MB WS2 xml response. See PICARD-581.
Add NEWS.txt
Remove unneeded imports
Minor tweak to display if variable is null string
Handle album finalisation correctly.
addrelease.py: Revert change to PLUGIN_NAME.

Per nikki's comment on pull request #271:
https://github.com/musicbrainz/picard/pull/271#discussion_r11242854