Address Early Adpoter's feedback

This PR addresses all of the points in the feedback as discussed in #8, for @honzajavorek to review & merge
Does

> [Type Name][] or full [Type Definition][] of the type to be included.

mean that Mixin is in fact enum with two options, Type Name or Type Definition? how does one know which one is it when there's no `class`? introspection?