[easytag] (7 commits) Non-fast-forward update to branch wip/taglib-mp4-cxx

[David King <davidk src gnome org>]

The branch 'wip/taglib-mp4-cxx' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  852fca2... Use C++ TagLib API for MP4 tags
  5393423... Support extended fields for MP4 tags
  41326a6... Add G_DECL boilerplate to picture.h
  b4000b6... Implement cover art support for MP4
  272daa3... Support album artist in MP4 files
  7a3e9d7... Use C++ TagLib API for MP4 header information
  b45fe1f... Avoid C++ string conversion warnings

Commits added to the branch:

  882f7ff... Avoid C++ string conversion warnings (*)
  c041532... Use C++ TagLib API for MP4 tags
  ef47696... Support extended fields for MP4 tags
  80d6140... Add G_DECL boilerplate to picture.h
  eed3e95... Implement cover art support for MP4
  ff80f91... Support album artist in MP4 files
  50e9980... Use C++ TagLib API for MP4 header information

(*) This commit already existed in another branch; no separate mail sent