Topic/responsetype

This branch/PR changes the behavior to require an explicit result type from a route. This is important to both make the response well defined as well as bring more type information along with the result.
Effects
* All responses must be generated with an entity generator, eg ```Ok("foo")``` as opposed to just ```"foo"```
* The response types can have headers added to them, exactly in the manner exposed by the core-dsl
* This also fixes the holes left by the recent refactor of http4s concerning ```Status``` and ```Method```
* Closes #20

@before, I would like to merge this sooner rather than later, as the master branch is broken and I would rather just fix it with this PR.