updated plugins version requirement (based on some errors in earlier version)
exporting the internal operations for LRWZVC, to support JIT
eliminating rewrite rules; won't be relevant for JIT with partial evaluations anyway
JIT implementation using System.Eval.

This works once. Unfortunately, System.Eval seems to be buggy.
All subsequent evaluated programs are returned identical to the first one.

(E.g. if we try `vrwlc` then `rwrwzwlwl`, the second compile will
 return the value from the first compile. This is quite annoying.)

I suspect I can address this by managing my own plugin files explicitly.