Checking for equality doesn't work with Flac as it does with ID3v2 tags

[IJabz]

From https://java.net/jira/browse/JAUDIOTAGGER-483

When working with the ID3v2 family of tags, I use the equals() method and it compares the contents of the tag, which is helpful to me, because it tells me whether or not I need to actually update the file.

When working with Flac tags though, testing for equality just appears to be the default, instance-level check, which always comes back as different and therefore always causes me to update the file on disk.

I think the difference in behavior is because in the AbstractID3v2Tag class, there is an override of equals() that compares the contents of the tags, but I can't find this for Flac anywhere.

I would be willing to take a stab at this if that helps getting it to happen.

[IJabz]

Actually I think only ID3 works in this way

[IJabz]

Checked and it was only working for mp3s, now modified so it works for other formats that use ID3 (wav and Aiff) but still to do for the others