More changes: - Details of changed properties now sent to subscribers - HubDbContext<T> now adds Select() callers to groups based on the passed predicate function. Currently supports operands that are constant & foreign key values.

More changes:
- Details of changed properties now sent to subscribers
- HubDbContext<T> now adds Select() callers to groups based on the passed predicate function. Currently supports operands that are constant & foreign key values.