added version control with paper_trail gem, added chat
removed paper_trail, switched most controllers away from Inherited Resources to allow for notifications to be pushed on successful creation/update etc
switched all Backbone templates to use HAMLC over ECO, added tracking method to application controller, removed message from activity model as differing message formats will be handled by model specific views
added activity ticker, amended PO history to work with new custom activity feed, fixed pdf output, restyled chat
added history to admin pages, moved url generation for activities to Activity model