Add AUX data for files processed using libmp4v2

I am aware of the patch found at
https://sourceforge.net/tracker/?func=detail&aid=2670433&group_id=129766&atid=715782.
However this does not use the new ITMF tags in newer versions of
libmp4v2.

I have modified the patch and added support for the following fields: -

TCOM - Composer
TENC - Encoding Tool
TRCK - Track Number (will use format <track>/<total> if possible)
TPOS - Disk Number (will use format <disk>/<total> if possible)
TIT1 - Grouping/Music Category
TBPM - Tempo/BPM
TCMP - Part of compilation (yes|no)
STIK - Media Type (see
http://code.google.com/p/mp4v2/wiki/iTunesMetadata#Media_Type_%28stik%29
for details)
TVSH - TV Show
TVES - TV Episode number
TVSN - TV Season
TPE2" || TPE4 - Album artist

You'll see that there are similarities as I based my code on the
previous patch.