[easytag] (4 commits) Non-fast-forward update to branch wip/easytag-next

[David King <davidk src gnome org>]

The branch 'wip/easytag-next' 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:

 http://live.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  e0a9d72... Add static to many declarations
  7d1ef2c... Use g_return_if_fail() and g_return_val_if_fail()
  61c8cdb... Avoid use of AC_CYGWIN and AC_MINGW32
  30e04a1... Simplify filename_to_display()

Commits added to the branch:

  c83b2bc... Add static to many declarations
  91e621f... Use g_return_if_fail() and g_return_val_if_fail()
  f68b92d... Avoid use of AC_CYGWIN and AC_MINGW32
  b945d8b... Simplify filename_to_display()