JDF-711 Override exception mapping for RESTEasy ReaderException.

Created a JAX-RS ExceptionMapper for the RESTEasy ReaderException.
This ensures that the default behavior of the RESTEasy exception mapper
to return HTML responses is overridden.

JSON responses are now returned if the client accepts them.

Also cleaned up the POM and removed direct dependency on Jackson Core.
The RESTEeasy Jackson provider brings this dependency as a transitive one.
Fixed failing Arquillian test.

Refactored the BookingServiceTest to ensure that ticket prices are chosen based on section and category instead of their index in the Set (which could change across JVMs).