Use named tuples for query parameters

[noelwelsh]

We extract query parameters by matching names to the query parameter part of the URL. The result of a successful match is a tuple ordered by the order in which the query parameters are specified. This doesn't keep the names, which is unfortunate since the names are usually more meaningful than the arbitrary order in which the QueryParams were specified. Named tuples allow us to keep the names around. Investigate using them for this case.

This will probably be easy to complete once form handling is done, as this will use the same techniques.