2.0 - refactor algorithms into modules

Decision modes don't make much sense. The core of this module are the algorithms. The distinction between selection and ranking is too subtle to be understood up front and the descriptions behind the voting mechanism now make much more sense to the user, but the plurality definition is hidden because it's really the only form of 'selection' mode... So we should probably kick out the door the concept of 'mode as modules' and really do 'algorithms as modules'. That would provide a nice layer between other voting systems in Drupal (like fivestar and voting API).

This could be the foundation of a 2.0 release