CanadaPost\Exception

The CanadaPost\Client class now throws a new type of exception -- CanadaPost\Exception -- when the CanadaPost API returns an error.  This differentiates those errors from errors from libcurl or elsewhere.
Router HTTPStatus => HTTP\Status

Changed some outdated references to HTTPStatus (which was changed to HTTP\Status) in the Router class.
Router URL Parsing Fix

Fixed the way in which the Router class parses URLs -- previously it was obtaining the URI with the query string.

Also updated it to use a centralized method -- the Server::GetPath method -- to get the URI, rather than unnecessarily implementing its own.
Server::GetURL Fix

Fixed a bug in Server::GetURL -- previously it was returning the URL with the path duplicated spuriously.
JSON::Send

Added a Send method to the JSON class.  This serializes a JSON object and sends it to the client.  It also optionally sends the appropriate Content-Type HTTP header for JSON encoded with UTF-8.