adapt for API change in ffmpeg 0.11

Replace av_open_input_file call, a similar fix is in chromaprint git.
Pull translations from Transifex
Use the new metabrainz.org URL to the donation page

http://tickets.musicbrainz.org/browse/PICARD-238
Ensure can_analyze's return value depends on the files / clusters of a cluster
Merge remote-tracking branch 'mineo/cluster-analyze'
Fix for broken $rsearch

return the first subgroup if there is one, otherwise return the whole
match.
Initialize format_context to NULL
Remove the hard-coded font from ui_options_tags
Make it possible to pass a filename when adding an image
Store lyrics language in tags instead of text representation language (PICARD-242)

This changes the meaning of the "language" tag. It is now no longer
derived from the text representation language of the release, but from
the lyrics language of the linked work(s).

The text representation language of the release is still available (e.g.
for scripting/plugins) as %_releaselanguage%. To get the old behavior
back, one must insert this line at the beginning of the scripting field:

    $set(language,%_releaselanguage%)

http://tickets.musicbrainz.org/browse/PICARD-242
Only store one identical language (PICARD-242).

Can happen if a recording is linked to >=2 works with the same language.
Fixup 835fa46.
Don't use _ as a name

Fixes an issue from the previous commit where I used _ as a temp
variable name. It only broke the infodialog, but I'm replacing it
everywhere just to be safe.
Ctrl-clicking in releases list pane requires clicking twice. (PICARD-248)
Don't use _ as a name, try 2

I screwed up the last commit.
Multi-select and drag+drop broken for new file tree (PICARD-246)
Prevent filebrowser from jumping when item is expanded
Merge branch 'PICARD-242-work-language' of https://github.com/weisslj/picard into weisslj-PICARD-242-work-language
Add a unit test for lyrics language
Prevent cover images from skipping numbers

This is a bug introduced with fc7470eee076c06d925598d3f29e7eca7cb089c6:
When saving multiple images with the generic filename, only odd numbers
would be appended to the filename, because the "while exists(foo)" check
is always true for every image except the first one at least once,
causing "i" to be incremented twice for every image (except for the
first one).
save_images: Use separate counters for different base filenames