Query param encoding issue

[rgalanakis]

There remains in #54 an issue with encoding of query parameters. Easy to repro by adding testUrlPath + "?a=b%3Dc" as a test url in TestRegisterResponderWithQuery. When using RegisterResponderWithQuery, the responder URL uses an unescaped query string (a=b=c), whereas the http request uses the original escaped query string.

I believe that #55 would fix this but haven't tried. I would submit a fix but I believe #55 is a better way to go.

[rgalanakis]

Just confirming that #55 fixes this issue and seems to work great.