Previously, if we were reading a file and encountered an ID3v2 tag after having already read one, we would overwrite the last one, losing all of its information. Now we preserve all of the information, overwriting frames as necessary.
This is an unfortunate compromise that needed to be made to make it possible to change the null separators in ID3v2.4 to slashes prior to returning the value.
V2 and V3 allow for the separation of multiple values with the solidus (/) character, while in V4 the separator is null (0). This was not accounted for previously, and would break valid V4 strings ("Foo / Bar" would be split into "Foo " and " Bar").
closes#82
This is the start of making Lofty more general purpose, allowing for the creation of custom tags.
This also makes `TagType::remove_from*` fallible, which makes much more sense.
The first MP3 frame behind metadata blocks is found by searching for frame sync bits.
This skips junk bytes between any metadata blocks and the first MP3 frame.
