Added "Profile" as a flag that can be used when building a project.  Since, if you try to use :exec within a repl, the profile flag is ignored by the Chez backend, without this flag, and there is no "profile" setting available within the "ipkg" file, there is not way to turn profiling on with the Chez backend.

Prelude.Types,
rather than Data.Nat, since "minus" actually lives there

Also modified test reg042 to include the new optimized stuff, and moved
it to perf009, since it's not really a regression test anymore.

…hez and

is probably closer to a performance test.

Reworked the test to examine the ".ss" file output to determine whether
performance improvements were made, rather than relying on clock on the
wall timing