API for post-hoc standardize_parameters() methods

[mattansb]

Needs:

• Multivariate model support ( support for post hoc standardization for multivariate models parameters#707 )
• Expand API for standardize_info()
• Have standardize_parameters.defauld() use standardize_parameters.parameters_model() for complete usage.
  (it should be possible to get the effect size without having to also call parameters!)

[mattansb]

Irrelevant.