- Adds dependency on regexp_parser
- Introduces a bijective mapper from regexp_parser expression to ast
- Extracts generic TypeRegistry
- Refactors Regexp::Transformer to use TypeRegistry
This change drops the concept of `excludes` from the corpus integration
configuration. Instead with `expected_errors` you specify errors you
expect to be raised by certain files. The corpus will fail if an
expected error is not encountered when mutating a file, or if an error
is encountered while mutating a file that was not whitelisted