This will raise the ```TagExcess``` exception only after running all the scenarios. The current version of cucumber raises the exception *before* running any scenarios which i *think* is the desired behavior.

Since parsing, compilation, and running are part of the same chain, replicating the existing behavior seems a bit complex at least to a cucumber codebase n00b.

When I was looking into it I contemplated an extra parsing pass outside of core but that seemed a bit gnarly.