Add defmethod and some uses of the deref operator

[water111]

Now we can do things like override the default print method

(defmethod print bfloat ((obj bfloat))
  "Override the default print method to print a bfloat like a normal float"
  (format #t "~f" (-> obj data))
  obj
  ) 

or print the parent type of the parent type of the type type.

(print (-> type parent parent))

This is working toward #49