Removed legacy display types. Redesigned the config page.

Removed legacy display types.
  AddThis module contained some small non generic display types. They where
  removed in favor of the display types added in the addthis_displays submodule.

Redesigned the config page.
  The settings page has been made more condensed and options have been merged
  into clear categories. There are some options that where removed because of
  legacy functionality that is now support inside the display types.