Merge commit 'b704b648'

* commit 'b704b648':
  mov: parse XMP metadata on demand

Conflicts:
	libavformat/isom.h
	libavformat/version.h

See: 054c506e

The default is left unchanged at enabled
We can change the default if people prefer but i do not want to do that
in a merge.

Merged-by: Michael Niedermayer <michaelni@gmx.at>