* Implemented filtering for JSON serialisation (only in Demo area)
- This is triggered by an 'expand' parameter that takes a string of CSVs, the values are of the form ModelName<dot>fieldName.
- E.g. 'Proposal.status' would serialise all 'status' fields for a Proposal. '*.status' would serialise all 'status' fields it can find. 'Proposal.*' serialises everything on a proposal (one level). Finally, *.* serialises everything.
- This is an intermediate commit, as the JsonUtil code will be refactored to make it more friendly. Also, the above documentation will be added to the README (in hopefully a more understandable way)