Webservice: generic JSON provider (#277, #278).

The Webservice module now offers a generic MessageBodyReader Provider for JSON reprensented entities (#277).
This means the application developer must no longer implement a custom provider class when she wants to deserialze an arbitrary JSON represented application object contained in the message body. She only must ensure the application object's class has a public constructor that takes a JSONObject as argument.
In other words: in your (REST) resource methods you can use an arbitrary class as the type of the entity parameter as long as the entity is represented in JSON and the class has a public JSON constructor. You are no longer required to implement a provider class.

Furthermore: the webservice's provider classes are generalized by exploting the fact that most DM core application objects implements the JSONEnabled interface. 6 provider classes are stripped from the webservice module (#278).

BREAKING CHANGES

DeepaMehtaUtils
    - relatedTopicsToJson() deleted

See ticket 277.
See ticket 278.
Consolidate JAX-RS provider classes (#277, #278).

Exception handling:
All provider classes throw a WebApplicationException.

Access Control Plugin:
"Permissions" provider class is deleted (it is not needed).

Close ticket 277.
Close ticket 278.