Lots of updates today

[Scott Wilson <sc...@gmail.com>]

Apologies for the large amount of commits today on the bean packages - this is partly to address a quite serious bug I discovered we'd introduced when switching over to JPA, and partly to try to simplify the models and reduce the volume of persistence code we're having to maintain.

The main changes are:

1. SharedData and Participant objects are accessed via the internal form of the SharedDataKey. The internal form is a hashed composite key to ensure uniqueness across host applications and widget URIs. This means there are no direct joins between SharedData, Participant and other beans such as Widget and WidgetInstance.

2. Access to SharedData collections is via a new service facade class, SharedDataHelper. I did this principally so I could cut out all the boilerplate in the IWidget and IWidgetInstance interfaces that has to be replicated for JPA and JCR implementations. `This facade doesn't actually do much other than convert the SharedDataKey to the internal form and then run regular FindByValue(s) methods, but it does ensure we have consistent access.

(Incidentally, I noticed that the classes in the "helpers" package aren't really all " helpers" as such - there are some View Helpers, some Factories and now a ServiceFacade among other "things" - so if anyone has a better way of organising and naming the classes please do contribute your ideas!)

S