ref: fe1211268d7d4e34cb96e8fbcfdd344af5e4e37f dhall-ruby/lib d---------
Bare minimum refactor to pass the metrics
Pass most compliance tests

No import or multiline string support yet
Beta normalization complete
Implement "shift" function for variable indices
All beta normalization except for functions
Remove swap files
First pass refactor
Implement many builtins and do Optional section
Start to implement normalization rules
Decoding Dhall from binary works