Refactoring: Implement DAOs using straight JPA

* Set the base packages of the classes to "com.ushahidi.swiftriver.core"

* At the implementation level, the DAO implementation classes
are now based on JPA but wired to use the Hibernate implementation
(of JPA)

* Replaced the "Hibernate" prefix in the class name the DAO implementation
classes with "Jpa"

* Changed the suffix of the DAOs from "DAO" to "Dao" for consistency
Remove service facades

* In our case,  there is no need for a facade layer to abstract
the services layer. All client requests are sent directly to
the services (which also handle transaction demarcation
and DTO mapping