Fixes #170 - implement usergroups

Added migration
Added tests
Added MVC files
Added the routes as well
Added the program logic and additional views
Added RESTful actions for update and create
Added validations to ensure that usergroup.name and user.login do not collide...

fixes #190 - Email report should be mime-wrapped

first host_mailer tests to complete

fixes #153 - EMail Notifications when hosts report failures

fixes #150 - Summary email ignores environment selection

fixes - #146 Adds a host environment and fact based filtering to Summarized emails

fixes #71 - send out daily email summary of puppet changes