All beta normalization except for functions

Remove swap files

First pass refactor

Implement many builtins and do Optional section

Start to implement normalization rules

Start creating comprehensive normalization tests

Take all the rules from semantics.md and turn each into a trivial test
case for that rule.  This allows TDD creation of the implementation of
the rules.

Typo

rubocop fix for Gemfile

Add backports for rubocop

Add initial COPYING

Decoding Dhall from binary works