Improvedquerystring

Hi,

First, I'd like to praise the team for the new router design. Especially the support for query strings is greatly appreciated! 

I've added support for query strings with multiple occurences of the same key. Instead of overwriting the previous value. The query string "?a=1&b=2&b=3" is now parsed as { a: '1', b: ['2', '3'] } instead of { a: '1', b: '3' }.