Simplify test setup with some macros

* package.lisp (route-packages): Export ROUTE-PACKAGES

* resting-tests.lisp (*use-this-acceptor*, *actual-port*)
(call-with-acceptor-setup, with-acceptor-setup)
(test-some-routes): Simplify test setup with some macros.
Allow extensions to specify content type

* resting-tests.lisp (parse-uri-1): New helper.
(test-parse-uri): More tests.
(test-some-routes): A new test.

* resting.lisp (parse-uri): Consider extensions. Use hunchentoot's
QUERY-STRING.
(parse-args-in-uri): Use hunchentoot's pre-parse QUERY-STRING
(resource-name-regexp): By default, the resource name never
includes the "."
(find-content-class): Improve docstring.