Add Data option to push. 

* bump to v.1.5
* Since dev changed significantly, had to refactor #88 into this version

@kitcambridge r?
Hmm, I think that's an empty case because `ParseMultipartForm` already handles multipart form decoding. But here, `url.ParseQuery(req.URL.RawQuery)` is parsing a URL-encoded query string, not a multipart form payload.