Handle proxy URLs

[iandees]

Some OpenAddresses sources are Esri layers behind an HTTP proxy. The URL ends up looking like this:

http://map.sccmo.org/proxy/proxy.ashx?http://10.10.143.115/scc_gis/rest/services/appservices/taxinformation/MapServer/0

from this build run

This URL currently gets parsed by the requests library and turns into a request like this:

http://map.sccmo.org/proxy/proxy.ashx?http://10.10.143.115/scc_gis/rest/services/appservices/taxinformation/MapServer/0&f=json

...which doesn't work, because the f=json gets passed as a query arg to the proxy.ashx script instead of getting sent to the Esri endpoint.

[marhensa]

same problem here

[ingalls]

I think this should be fixed by: #38

@iandees are we ok to close?

[iandees]

Yea, I think so.