added APIs to list and show trip tickets belonging to an originator
moved trip ticket filtering code to a reusable module and included it as an API helper
added CanCan support to API, need some helpers to dry up the repetitive code
completed API crud operations for trip tickets except for cancel/deactivate which is pending model support, added section to CanCan abilities for API user,  added rspec tests for new API ops
removed some TODO comments and unnecessary associated objects from the TripTicket Grape entity
added a line to .gitignore
Merge branch 'master' of github.com:rideconnection/clearinghouse into 1041_api_crud_for_trips

Conflicts:
	app/controllers/trip_tickets_controller.rb
	app/models/ability.rb
added rspec-rails to Gemfile development group so 'rake spec' can be used to run rspec suite
fix for errors in API caused by changes to user roles
Merge branch '1041_api_crud_for_trips'