Code dump

This code pretty much does nothing: it passes an input Flo file
directly through to the output through libflo.  Essentially this means
that "flo-opt" currently does exactly what "flo-canon" does.

There's also some machinery for running test cases using
"flo-patterns" (part of "chisel-torture") that ensures that the
optimized version of a Flo file computes the correct answer.