Also, fix Makefile.release on a Mac.

This allows the examples to be created without having to install
an XCVB. The primary implementation is in bootstrap.lisp and
additional code in driver.lisp.
+ The created XCVB is made with one of the supported lisp
implementations even though the enclosing lisp invocation might
not be.
+ Refactored lisp-invocation into its own package.
+ The cache-description file contains notes about how the cache
should function. The cache is both the multi-user cache as in
distcc, ccache, etc, but also the user specific workspace for
where to dump fasl files and whatnot.

* 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

Move more release code from Makefile to CL.
Fix shell-tokens-to-Makefile on CLISP (CLISP bug in loop, or my misreading the spec?)
Fix some tests, make them more verbose.
Driver: Fix native-namestring on SCL; fix issues on CLISP:
Setting the *source-file-types* and *compiled-file-types* to nil
was preventing (require "linux") from working(!).

Move fake-release-directory to Lisp.
Fix enough-namestring in Makefile.

driver: fix back the allegro run-program after latest changes
tests: refactoring so xcvb-driver-test can be run independently
other: fix some missing renamings of escape-shell-token.

Try to make it work with gcl - but gcl fails to compile driver.lisp.

run-program/process-output-stream and slurp-stream-*.