Orphan UI (rough draft)

* `/orphans` is a page for admins with:
  * orphan orgs listed, each with buttons to generate a user and return a password reset token
    * jQuery is used for this operation, so no page reload happens (the intention is that finding the result in a large table after a page reload might be difficult)
  * orgs with robo-generated users

* this feature is nearly fully tested
 * `features/admin/orphan_orgs.feature` is the cuke
 * `spec/models/organizations.rb` contains tests for the scopes and the `generate_potential_user` method
 * the orphans controller has specs
 * the jQuery has specs
 * the view is not unit tested, as it is most likely to change

* TODOs:
 * refactor UI to allow batch processing of user generation (use checkboxes instead of buttons)
 * allow table columns to be sortable (see jQuery's famous tablesorter plugin)