mmcgrana/ring forked from ring-clojure/ring

Cookies still need to be www-form-urlencoded using the URLEncoder
and URLDecoder classes to maintain backward compatibility.

Java's URLEncoder and URLDecoder classes don't follow the URL-encoding
format precisely, instead encoding strings in the slightly different
www-form-urlencoded format. This commit ensures that the url-encode and
url-decode functions work correctly, leaving it up to the form-encode and
form-decode functions to handle data encoded in the www-form-urlencoded
format.

Refactor parameter parsing

- Add a test for :max-age and :expires to (wrap-cookies ...). There were
  no real tests to exercise the base input cases (int, string) which the
  comment block states. This test just makes sure it fulfils that
  contract.
- clj-time is now a project dependency
- :max-age accepts an Interval as input. Updated (write-attr-map ...) to
  accept an Interval (from JodaTime) as well as an int. The interface
  from clj-time is used.
- :expires accepts a DateTime object. It converts the DateTime object in
  the equivalent RFC822 which the cookie spec requires.
- Added pre-conditions for :max-age and :expires to make sure that they
  only accept Interval and DateTime, respectively.

Replace this with (zero? ...)