Refactor of API to be more testable and use JSON.NET serialisation

 #4 Determine JSON serialisation to use within the API 
- Removed the FemahApiHttpHandlerFactory so we can override ProcessRequest in the HttpHandler and use the far more mockable HttpContextBase 
- Added 3 basic unit tests for the API 
- Took a dependency on the the JSON.NET serializer - Implemented tolerant JSON reader tests as per issue #4