Custom JSON formatting attributes on models are ignored

[GraemeF]

This is because in order to add the HAL objects to the model it is converted to a dynamic, so when it comes to serialization time there is no class definition to read custom serialization attributes from.

Not a major issue, but thought it was worth mentioning somewhere as it took me a while to realise why they weren't having effect!

[drewfreyling]

+1 this needs fixing

[danbarua]

This might need a change to how we approach things - as implemented, it is serialiser-agnostic, it simply swaps your model out for a dynamic.