fixes #812 - new permissions model, user group role and nest support, role filters for better granularity

• Daniel Lobato <elobatocs@gmail.com>
• Joseph Magen <jmagen@redhat.com>
• Tom McKay <thomasmckay@redhat.com>
• Greg Sutcliffe <gsutclif@redhat.com>...

fixes #4393 - rename ancestry label to title

fixes #3912 - add inheritance for locations / organizations

Fixes #3720 - Add description field to operatingsystem

fixes #2871 - params search works with nested hostgroups

fixes #2739 - add ActiveSupport::Concern syntax to mixins

fixes #2411 - move files in /models to /concerns, /services, /mailers, /observers