Fixed corner bugs in the package surgery.
Stopped using fmakunbound as part of the package definition;
it should happen as part of with-upgrade,
or, for now, systematically with defgeneric* and defun*.
Added special magic for ASDF fixup, that will have to be enhanced.

New pathname functions to work around more logical-pathname issues.
See discussion with rpgoldman on asdf-devel, and see CCL ticket:953.
Also, tweak build to reflect recent refactoring of asdf.
WIP of define-package work needed for clean upgrade (still broken).

TODO: Create a define-package that can make it upgrade itself.