Classes generated by deftype and defrecord don't play nice with .getPackage

Classes generated loaded by DynamicClassLoader return nil for .getPackage. Tools like CIDER and vim-fireplace are relying on this information to implement things like completion hints.

Proposed: During DynamicClassLoader.defineClass(), invoke definePackage() on the class being defined (similar to what URLClassLoader does).

Patch: clj-1550-v4.patch

Screened by: Alex Miller