Next version of Addthis module

Addthis API 2.0 offers new functionality and should be implemented in this module. This will happen before D7 port of the module. There is a number of feature requests in the issue queue and now is the time to work on them.

This is also likely the last major upgrade to this module before trying to work towards making just one social bookmarking / sharing module for Drupal that would combine all existing ones. Many module authors are now working on same basic functionality and only small parts of these modules are really unique to each project.