Improve Closette boostrapping.
Improve Closette boostrapping.

The bootstrap code has been moved into a function and is only run
when Closette.lisp is loaded for the first time.
This is a step towards allowing Closette to be reloaded, without
hosing any existing classes/generic functions/methods.

rvedam/Mezzano,varjagg/Mezzano,rvedam/Mezzano,varjagg/Mezzano,froggey/Mezzano,froggey/Mezzano