Modified generation of "essential" .lisp files by improving comments about evaluation, in particular for in-package forms.

Fixed Lisp package issues.

Updated to the latest version (3.4) of ACL2 and did some
reorganization and addition to support regression testing.

Pathnames only need to be edited in one place now:
.acl2holrc.bash

Edited and added README files. In particular, tests/README explains
how to run the new tests.

Deleted lisp/defaxioms.lisp.trans, an updated version of which is now
in tests/round-trip/gold/axioms.lisp (corresponding to ACL2 Version
3.4).