Test the systems in systems against each Lisp implementation in lisps.
The keyword parameter systems can by a list of system names or the keyword
:all. In the later case, the current list of systems will be pulled from the
CLiki. It defaults to the value of *systems-to-test*. The keyword parameter
:lisps should be a list of implementation names as keywords. It defaults
to the return value of the li:first-implementation (which ought to be
the lisp currently running).

Each system is tested against each lisp using the following steps:

1. A file 'startup.lisp' is created in a sub-directory of the working
directory named after the lisp being used (e.g., 'sbcl' for :sbcl).

2. A new process is created which starts the child lisp using
startup.lisp to initialize it.

3. The startup.lisp contains the commands necessary to use ASDF-Install to
pull the system being tested and compile it. All output from the lisp process
will be saved.