Initialise class for to and from

[djsuperchief]

There may be a situation where headers do not cut it for initialisation data. For instance, you may need to be able to specialise a payload. This could probably be done with extension methods but it is worth investigating whether there is going to be much call for initialisation class and data as part of the core or as part of a component.

Example, REST component will need to be able to specify a data set to post etc. This cannot be done in headers easily or in an easily readable manor.