Clean up in test cases.

Correctly close ApplicationContext created in test case to avoid compiler warning. Removed unused method from PaymentProcessIntegrationTest. Moved PaymentProcessIntegrationTest into payment.web package.
Upgraded to Spring HATEOAS 0.6.0.SNAPSHOT.
Removed explicit reference to EMF for JpaTransactionManager setup.

JpaTransactionManager now automatically finds default EntityManagerFactory (as of Spring 3.2) so that we don't have to explicitly configure a reference.