This new class stores the image data in a tempfile.TemporaryFile so we
don't keep the data for all images that are used somewhere in memory
anymore.
It also deals with saving images onto disk when the corresponding tracks
are saved (this was previously done by the File class). This removes the
ability to use tagger script in the cover file name (cf. the first line
of File._make_image_filename).
Context menu listing other releases is using main information from release,
often it is enough, but sometimes two or more items in the list are exactly
the same, user have to select each one to determine which is matching for him.
This patch is improving a bit the situation by adding packaging, barcode, or even
disambiguation comment if needed.
As an example, it often happens when a CD is released in jewel case and digipak,
with same label, date, country, barcode, etc..
Use more explicit '[no barcode]' instead of '[none]'.
A test case was added for this feature.
When file has no metadata field indicating the track number, Picard
is trying to guess it from filename, but the simple regex wasn't very efficient.
tracknum_from_filename() does a much better job.
A test case was added.
version_info was renamed PICARD_VERSION
version_string was renamed PICARD_VERSION_STR
short version string is stored in PICARD_VERSION_STR_SHORT (for display)
Hooks can be created to handle upgrades (ie. options renaming), see config.register_upgrade_hook() and config.run_upgrade_hooks()
Binary and decimal modes are supported (MB and MiB ie.)
It supports i18n using gettext and locale.
Precision can be modified if needed, by default it is using 1 digit (if needed).
Extensive tests were written, the toughest was to make them work for
both default C locale and fr_FR.UTF-8 locale (ofc it is possible to test for more
locales...). If one locale isn't available on testing system, test is skipped.
fr locale was chosen because decimal point is replaced by a comma and byte units
becomes "octet" units (1.5 MB in english -> 1,5 Mo in french).
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.
