This may be another case of our tests not actually testing to the extent that we expected, but does entering just 'bob@example.com' no longer work? I notice this change in a lot of tests, and I'm just curious if the functionality has actually changed, or it they just weren't great tests to begin with.

Besides this question and the note above, I think the rest of this pull request looks good, awesome work.  The addition of the {StartRule: ''} thing seems like an unfortunate side effect we'll have to live with, but it's not that bad and I don't think I've ever debugged deep enough for that parameter to make a difference to me anyway, the Grammar was usually just a black box.

I also don't really understand the commit for making debugging easier by putting new lines in, but it's really not big enough of an issue to make an argument to revert.