[easytag] (11 commits) ...Add test for ET_File_Description functions

[David King <davidk src gnome org>]

Summary of changes:

  b1242ae... Add File_Tag struct setters (*)
  3377420... Make ET_Set_Field_File_Tag_Item() static (*)
  9e855c1... Split a couple of enums out to a new core_types.h (*)
  bb9ce6f... Move EtPicture declaration to picture.h (*)
  86f79e4... Split off File_Tag to a separate file (*)
  7c12ed0... Move two more struct declarations to core_types.h (*)
  d639f6c... Split ET_File_Description out to separate file (*)
  103c202... Split majority of et_core.c out into new file.c (*)
  c5abfa4... Split ET_Core list handling code off to new file (*)
  94da689... Simplify ET_Core from four functions to two (*)
  e87b62b... Add test for ET_File_Description functions (*)

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