Make the request resonse cycle stateless

Assumptions about deferred objects were creeping into the code that could have lead to state changes. This makes the code look a little wonky, but it fixes those state problems.

Specifically there was an assumption that each endpoint only needed one Q.deferred object. Simply not true. An endpoint needs a Q.deferred object for every request made to the server. This is accomplished by wrapping Q.deferred creation into a closure which scopes the deferred into the callbacks of the promise. This keeps the MethodFactory objects stateless between requests, as the state is stored in a closure that called every time a new request is sent.
Give deferred object creation function a better name
Decouple deferred generator and move it to its own module
Make the interface of genDeferreds returned object more deferred like
Merge pull request #17 from kahnjw/fix_state_problem

Make the request resonse cycle stateless