Clean up various printing bugs.
Add command line switches to control CP evaluation tracing.
Fix partition of fragments when commuting output.
Add various natural number of stream-of-naturals examples.
Remove quoting from bit string example.
Change CP syntax of first-order send and receive to look like pairs
instead of looking like quantification.
Closures for GV.

The CP translation for GV code that relies on closures seems to be
broken---I've included a representative test case (closures.gv).  I
haven't attempted to track down the cause of this problem yet.
Change GV binder syntax from "." to "=>" to avoid confusion with dots in
types.
Update README to reflect current build instructions.