Make sure connection params are reset between stateless requests

Introduces a `connection#resetParams()` method that can be used instead of overwriting `connection.params = {}`.  In addition, this calls `resetParams()` in the webServer connection object after rendering the response to the browser.  This is necessary because otherwise the action params linger after the request has already been handled, and since HTTP is a stateless request, those params should not linger after the response has been sent to the browser.