'predicted' and 'results' functions vs use of a mapping class

[grlloyd]

Functions 'predicted' and 'results' allow different outputs to be used as the input to the next model when using e.g. model.lists or chaining together iterators.

A better approach might be to create a 'mapping' class where the outputs from one object are explicitly assigned to the inputs of the next. This would allow more flexibility and streamline e.g. using VIP rank as inputs for Forward selection, and allow multiple outputs from one model as inputs to another. mappings can be auto-generated when creating an object if output names match input names, for example, but changed by the user for bespoke applications.

Unsure how this would work in galaxy environment.