Reduce code redundancy using a generator
Move code generating py file name fro ui file name to its own function.
Add --files= option to setup.py build_ui, to pass list of files to rebuild

Related to http://tickets.musicbrainz.org/browse/PICARD-566
Add missing whitelines.
Allow compilation of ui files in unusual directories.

.py file will be produced in the same directory of the .ui file
Drop time-stamp comparison, remove variable comments from generated files.

See discussion at http://tickets.musicbrainz.org/browse/PICARD-566
Fix error on malformed TRCK tag.
Provide error log on invalid format.
Provide same checks for TPOS
Match TRCK and TPOS using regex and reduce code redundancy.
Use re named groups to match values and metadata keys.
Merge pull request #1 from zas/tpos_trck

@zas: Match TRCK and TPOS using regex and reduce code redundancy.

@sophist: I wondered whether this code was too difficult to read, but in the end decided it wasn't.
Update NEWS
Restore time-stamp check, files depends too much on uic versions anyway

It works in most cases, and now one can force regeneration of one or more files
if needed.
Merge branch 'sophist_fix_error_on_malformed_TRCK_tag' of git://github.com/Sophist-UK/picard into Sophist-UK-sophist_fix_error_on_malformed_TRCK_tag

Conflicts:
	NEWS.txt
Merge remote-tracking branch 'upstream/master' into build_ui_improvements
Update NEWS.txt
Merge pull request #266 from zas/build_ui_improvements

Add --files= option to setup.py build_ui
Regenerate .py files from corresponding .ui files
Update translations