Opening read-only files.

[earboxer]

Currently, opening a read-only file fails. This is because id3.Open opens the files in read write mode (os.OpenFile(name, os.O_RDWR, 0666)).

One thought I had would be to fallback on read-only mode if readwrite mode fails. Then we could just throw an error if someone tries to write to the object. (is it still considered a breaking change if it changes when an error is given?)

Probably the least offensive change would be adding another function, maybe called Read, which would be just like Load, except with os.O_RDONLY. Would that be more confusing?

[richdawe]

I think you can achieve something similar by opening the file read-only and then passing it to id3.Parse(), https://github.com/mikkyang/id3-go/blob/master/id3.go#L50