add endpoint for displaying token

@liggitt This builds on top of pull/334, but I'd like to go ahead and get a review.
> I'm not in love with these paths.

@smarterclayton I view this whole thing as scaffolding until we get a pretty UI for token management, but if it's important enough to change, I'll need a suggestion.  I asked Jordan for names (with no biasing) and he came up with the same thing.