[easytag] (12 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:

  60d4ac0... Support extended fields for MP4 tags
  4b56861... Add G_DECL boilerplate to picture.h
  9c1eddb... Implement cover art support for MP4
  35ae720... Support album artist in MP4 files
  e7b3f28... Use C++ TagLib API for MP4 header information
  0044b87... Add GIO/TagLib compatibility layer
  ce5a17d... Clean up GIO TagLib wrapper
  c490b3a... Use GIO wrappers in mp4_tag.cc
  b2a8bf0... Use GIO wrappers in mp4_header.cc
  a0c16dd... Detect good set of warning flags for C++ compiler
  d0e1f6c... Improve error handling in GIO/TagLib wrapper
  beb0f9a... Add basic error reporting to mp4_tag.cc
  122aacc... Add basic error reporting to mp4_header.cc
  35bfa52... Remove auto pointer template

Commits added to the branch:

  b212845... Detect good set of warning flags for C++ compiler
  63fe527... Support extended fields for MP4 tags
  c8688d3... Implement cover art support for MP4
  ae73293... Support album artist in MP4 files
  dd4e526... Use C++ TagLib API for MP4 header information
  51d9af3... Add GIO/TagLib compatibility layer
  f0a7bf5... Use GIO wrappers in mp4_tag.cc
  6598df0... Use GIO wrappers in mp4_header.cc
  a2d1dbd... Improve error handling in GIO/TagLib wrapper
  2958b29... Add basic error reporting to mp4_tag.cc
  4ba0cca... Add basic error reporting to mp4_header.cc
  123d009... Remove auto pointer template