Add 'Audio' to the categories in the .desktop file

As per
http://blogs.gnome.org/hughsie/2013/09/03/broken-desktop-files/
it should have both 'AudioVideo' and one or both of 'Audio' or 'Video'
in order to be categorized correctly.
Merge pull request #157 from kepstin/desktop-fix

Add 'Audio' to the categories in the .desktop file
Add more info to release name in other releases list if needed.

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..

A test case was added for this feature.