refactor HTTP tests

Make tests DRY by factoring out the setup into
a separate function.

Rename the tests to namespace functionality for better
understanding of what is being tested.
allow an Error object to pass back its message attribute in the default error blueprint
allows an error to be sent to a policy middleware callback. Fixes #329
add http policy tests
fix args.length check
Merge pull request #329 from particlebanana/policy

Policy Middleware Doesn't Fire Default Error Handler