[2.0.0b4] quicktime, suppoprt for "covr" atom

[indeyets]

looks like getid3() is not aware of "covr" itom in quicktime (m4a in my case) files.

iTunes stores album art (album "cover") information there.

there is the description of iTunes specific atoms here:
http://atomicparsley.sourceforge.net/mpeg-4files.html