ENH: Enable updating prefix through property setter.
Merge pull request #115 from danielballan/prefix-property

ENH: Enable updating prefix through property setter.
Make param_names a property that is always updated in composite models. Fix #116.
For composite models, add also parameters from hints to param_names property
Merge pull request #117 from tritemio/master

Make param_names a property that is always updated in composite models.