Add Data option to push. 

* bump to v.1.5
* Since dev changed significantly, had to refactor #88 into this version

@kitcambridge r?
Ok, thought about it some more and added a custom Form Value reader. It *tries* to do the right thing and limits the data that can be sent in. I'm also a bit surprised how few testing frameworks set the Content-Type correctly, so I try to deal with that as well.