Add Servant recipe.

Hey guys,

I wrote this Servant package, which is an Elpa server. The main reason that I wrote it is because Cask uses a fake Elpa server for the tests and Pallet will most likely do so also in the future. I just figured it made sense to have such a package.

I don't know what server and build tool you guys are using to host your server, but it sure would be awesome if this package would be "the package" for hosting Elpa servers.

I wrote this package today and I don't even have any tests yet, so of course it would take some time to get there.

What do you think?