Create OptionsListener

- Takes configuration, and runs at "route" event at -100 priority
- Tests to see if a route identifier was provided; if so tests against
  entity_http_methods to see if the incoming request is valid. If none
  is provided, tests against collection_http_methods.
- Will replace functionality in the RestController.
Created factory for OptionsListener

- created factory for OptionsListener; passes zf-rest configuration to
  listener at instantiation.
Register OptionsListener during bootstrap

- Added factory to configuration
- Register listener during bootstrap
Removed HTTP method negotiation from RestController

- this is now handled by the OptionsListener
- OPTIONS requests are still handled by the RestController, however. This is due
  to the fact that it triggers events, and changing those events at this time
  would be non-BC.
Ensure HTTP method names are normalized
Merge branch 'feature/options-validation-listener'

Close #20