net/request

This is still WIP. However wanted to discuss a few things.
I wasn't quite sure if we should mock the tests using fake Request class provided by [Jasmine](https://github.com/pivotal/jasmine-ajax) or [Sinon](http://sinonjs.org/docs/#server).

I'm mentioning Sinon here as I find Jasmin's approach and syntax rather cumbersome on.

Also - suggestions on how to test the headers and parameters?

/cc @conradz @millermedeiros