[gthumb/ext] (18 commits) ...Merge branch 'gstreamer' into ext

[Paolo Bacchilega <paobac src gnome org>]

Summary of changes:

  4724dc5... read audio/video metadata with gstreamer
  5874c2b... make a formatted version of the duration field, added the b
  41b1c63... unified duration and dimensions metadata for videos and pic
  a2c124f... added gstreamer to the default extensions
  8580d66... removed unused variables
  07c6c2d... added a video player
  5a49f94... removed unused variables
  91640f9... set the playbin state to null before loading a new file
  a9089ab... added a mediabar at the bottom
  dfa4ccb... implemented other player commands
  cb73b70... added a mutex to make the register function thread safe
  6a4f9c1... start work on a video screenshot command
  80c950c... hide/show the mediabar when in fullscreen mode
  153b1b7... fixed video area redraw
  c8914a4... do not hide the controls when the mouse is over the mediaba
  05cef3d... added a fullscreen button in the media viewer toolbar
  e22ba0b... added ability to save the video screenshot
  fcf55c9... Merge branch 'gstreamer' into ext