Add test for parsing multiple CFRs
Add test for parsing multiple CFRs

- Ensure that leading and trailing whitespace are stripped
- Refactor existing test to not rely on order in which parse
  results are returned

tadhg-ohiggins/regulations-parser,eregs/regulations-parser,tadhg-ohiggins/regulations-parser,cmc333333/regulations-parser,eregs/regulations-parser,cmc333333/regulations-parser