Fix current_page? to work with multiple parameters in the query string

The current_page? helper method currently doesn't work correctly if you have multiple params in the url as the CGI.escapeHTML call turns the ampersands into html entities which will fail to match the url from the request.

The attached patch changes the CGI.escapeHTML to a CGI.unescapeHTML so that any url passed to the current_page? method that may have been generated by a named route helper method will match as these are already escaped by default.

Includes three tests - the first is just a baseline test to make sure that current_page? is working with simple urls. The second test checks the recently added ability to ignore url params which fails when passing a hash as the route generated includes the params from the current request. The third test checks for explicitly passed urls with multiple params.