improve node.js test with streams

the point of node.js is streams and your tests didn't utilize them. i updated the code to stream the JSON response and refactored the code since you have so much repetition. yes, this is more complicated, but because of that, i wouldn't bother updating the express test.

i don't know why you guys `process.nextTick()`d `mongodbDriverQuery` but it's pointless. you did some other silly stuff like `x < '10'` and `x += 1`. using `collection.find()` when you only want a single document. creating unnecessary closures in `mongooseQuery`. not returning the callback in `mysqlQuery` which would cause so many problems for people in real apps. you should apply these changes to the express test as well.

this is also not tested because this suite takes too much effort to setup. let me know if you guys run into issues.

also, i'm not sure how this tests work, but you may not want to write non-existent documents, so you might want a `if (doc) res.write(doc);`.