Add hu.dwim.defclass-star

[Ambrevar]

I find hu.dwim.defclass-star to be one of the most convenient defclass wrapper.

It adds a very useful :export keyword to slots as well as class options such as functions to derive the accessor / initarg names from the slots.
It can also automatically export the class name and the slot names at compile-time.

I would recommend it over defclass/std in particular.