Added 'Mark Odd/Even Rows' option, under the View menu. When it's turned on, the odd and even rows are displayed in different color, to make it easier to read a single line.

NEW: added new field UserAgent for web sources which enables sending Mp3tag/#.## as
user agent if set to 1.
[2011-05-19] CHG: updated MusicBrainz web source.
[2011-05-15] NEW: added %rate% for MP4 file
[2011-05-15] NEW: added %keywords% for MP4 files.
[2011-05-15] NEW: added support for preserving unknown MP4 atoms when writing tags.
[2011-05-04] NEW: added cover-specific %_cover_type% at action Export cover to file.
[2011-05-04] FIX: action Export cover to file duplicated file extension for multiple covers.
[2011-04-18] NEW: support for inbuilt parameters MP3TAGAPP and MP3TAGAPPDATA for $getEnv.
[2011-04-18] CHG: replaced discogs web source by web source based on discogs web service.
[2011-04-07] CHG: updated discogs web source.
[2011-04-03] NEW: added support for wildcards in format string of action Import cover from file.
[2011-04-03] NEW: added support for wildcards in format string of action Import text file.
[2011-04-03] NEW: added %rating winamp% for MP3 files.
[2011-03-26] FIX: possible runtime error when creating new actions.
[2011-03-25] NEW: added %itunesaccount% and %itunespurchasedate% for MP4 files.
[2011-03-22] FIX: $rand was only seeded once per session.
[2011-03-22] FIX: $ifLonger did not work as documented.
[2011-03-21] NEW: added %_video_height%, %_video_width%, and %_video_bitrate% for MP4 video files.
[2011-03-21] NEW: scripting function $getEnv.
[2011-03-21] NEW: support for Unicode encoded web sources scripts.
[2011-03-21] FIX: runtime error at converter preview with empty format string.
[2011-03-20] CHG: removed action type 'Shorten filenames to 64 characters'.

* Firefox 5: add support for Firefox 5.