Fix up restify's Request/Response interfaces

 * `restify` is quite explicit about the log having to be a `bunyan` logger. Makes life a lot easier using it to just make it so.
 * Looking at the 2.8.4 source most of the `Request` properties are implemented as memoized getter functions, not just plain properties.
 * The tests were defining a function with implicit `any`s as the parameters and not actually testing any properties...