[easytag] (9 commits) Non-fast-forward update to branch wip/opus-support

[David King <davidk src gnome org>]

The branch 'wip/opus-support' 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:

  82bf6b5... Support reading tags from Opus Ogg File
  300ac31... Improved support for Opus files.
  9804126... Add support for writing Opus Tags
  93d669e... Improved support for writing Opus Tags

Commits added to the branch:

  17fa304... Add British English translation (*)
  1f8be85... User docs: Make page ID the same as file name (*)
  15b332d... Updated Serbian translation (*)
  8d5b0e9... Fix a double free when opening a command-line path (*)
  86d61b6... Updated Polish translation (*)
  12a6ef9... Use G_BEGIN_DECLS in more headers (*)
  47754d8... Avoid a potentially-uninitialised variable (*)
  9287ee0... Support reading tags from Ogg Opus files
  8609f1a... Support for writing tags to Ogg Opus files

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