* Use define-command to define and register a command
* Introduce the notion of workspace to store intermediate and target files.
* Update Makefiles for new intended output paths

* makefile backend bug: make was doing the wrong thing when a.fasl depends on b.cfasl
  which depends on b.fasl. Apparently, when b.fasl was recompiled, a.fasl wasn't recompiled
  until the next run of make; we ensure it will by having a.fasl depend directly on b.fasl.
* move code around: remove style-warning when loading master as lisp.
* have master explicitly support pathname arguments
 (though princ must have done the right thing already before then).
* more moving code around: move specific commands out of main.lisp.