Add support for truly values
Add support for truly values

 - Parse truly values in querystring (e.g. ?bar&foo=42 => bar is `true`)
 - Stringify truly values ({ bar: true, foo: 42 } => foo=42&bar)
 - Small syntax changes.
 - Return undefined for fields that do not exist in the querystring snippet.

jillix/url.js,jillix/url.js