First draft of redex core language.
Removed annotation from core language
Added type reduction and infer-core

* Can't get β-equiv rule to work, so normalize types then check.
* Added infer-core, a closer to surface language on which to do
  inference.
Fixed rule names, working on type inference
Added inductive types; assorted fixes

* Fixed variable typing; weakening is no longer a rule but built into
  lookup logic.
* Fixed substitution.
Module language, positivity checking, more tests
* redex-core is now a module language, complete with fancyness. For
  documentation, TODO.
* Added examples file using the module language.
Renamed to racket-cic; language are cic*
Extensive examples, syntax extensions out of core
Fixed missing universe rule
Serious reorganization of examples file
Added implementation of proofs for free extension

* Implemented the dual-mode extension to proofs for free, complete with
  a neat theorem.
Fixed to well-formed env, tinkering with PFF