fixes #38 return key/prop combined object.

This currently only patches `.get` & `.getAll` to return a single array of combined key/property objects. I will move on to `query` if this seems headed in the right direction :+1: 
I meant to ask about that :) The line now reads `if (err) {` -- I didn't think we'd classify no results as an error, so it instead will call the callback with callback(null, undefined). Is that the correct behavior?