Add failing test
Add ‘fo’ token parser
Merge pull request #2 from trailofbits/failing-parser-test

Add failing test
Use match['...'] for multiple-choice letters.
Simplify fo parsing with match
Merge pull request #3 from trailofbits/add-fo

Add ‘fo’ token parser
code climate
Add DMARC::InvalidRecord
Use custom #original method for exceptions