Add lti config for custom field name and consolidate authn providers
Add more config options for lti

- Added vine gem that allows dot path lookup for hashes
- Implemented path lookup for lti config
- Added more options for lti config
- Added an example lti configuration file
Remove IU specific lti config
Dereference class ID to class name in facets and search displays
Move mapping of LTI params into omniauth-lti
Make sure Avalon::Lti::Configuration is set when there is no config file
Change deprecated controller#method_missing to #action_missing
Allow LTI consumer to specify a media_object_id to jump to directly
First stab at LTI tests via omniauth_callbacks_controller
Session specific values should live in user_session and not on the user model
Updated Gemfile.lock
Fixed path to virtual_group that wasn't fixed in rebase
Refactor ability and fix VOV-2353
Move omniauth_callbacks_conroller_spec.rb from spec/controllers to spec/integration to use the whole middleware stack
Replace Course#guid with #context_id
Update User model to use auth_hash.extra.consumer hash
All existing omniauth callback controller tests passing
Rearrange callback controller specs to put all LTI tests under an 'lit' context
Partially revert e09d2c6; improve tests around it
Fixed a missed guid -> context_id change