libgd: Added libgd to cut-n-paste

A separate commit where libgd is added to cut-n-paste. libgd is used for the bookshelf
view of recent documents.
libgd: Use cairo surfaces instead of pixbufs in gd_embed_image_in_frame
libgd: Expect a cairo surface instead of a pixbuf for the GdMainIconView cell renderer
ev-recent-view: Added bookshelf view for recent documents

* Files are added to the bookshelf only if they exists
* Use gtk_recent_info_get_modified instead of
  gtk_recent_info_get_visited for ordering the recent items.