url interpolation: add support for querystring

[purpleKarrot]

Make sure that all four varriables get interpolated in the following url: /:var1/:var2?foo=:var3&bar=:var4.

This can be done by replacing the regex /:[^\/]+/gi to /:[^/?&]+/gi here: https://github.com/MithrilJS/mithril.js/blob/next/request/request.js#L144

Note also that the / does not need to be escaped.