Use Yesod when testing Haskell

[mihaimaruseac]

Yesod is faster than snap, can you please use it as well?

[ericmoritz]

I'm not a Haskell developer. The snap implementation was build by folks in #snapframework on freenode. If you could write an separate implementation and submit a pull request, I'll pit it against snap and the others the next time the benchmark is ran.

Thanks,
Eric.