Meta Data Support for M4A

[pschatzmann]

I am looking for someone who is willing to extend the functionality to add meta data support to the M4AContainer.
This should not be to difficult to implement:

We just need some new parser callback for the meta

[meta] ; Metadata box
├── 4 bytes: version and flags
├── [hdlr] ; Handler box (usually "mdir")
└── [ilst] ; Item list box
├── [©nam] ; Title
├── [©ART] ; Artist
├── [©alb] ; Album
├── [©gen] ; Genre (string)
└── [gnre] ; Genre (numeric ID)
└── [covr] ; Cover image (can be large)