TODO
====
- orderasc is not treated in adm javascript - do we need it 
  for the shortcode generator? 
- update shortcode generator to include ordertype and orderasc (see above)

- double previous: PiwigoPress_previous_options and PiwigoPress_previous_url -> unify
- support for oembed, register as oembed provider???
  http://codex.wordpress.org/Embeds
  http://codex.wordpress.org/Function_Reference/wp_oembed_add_provider
  http://codex.wordpress.org/Function_Reference/wp_embed_register_handler
- export the created IMG also as // instead of http(s)://
- allow for a mode to include the actual html code instead of a short
  code - this is necessary for open graph photo scrambler
