MIRTH-1861: Added proxy support to the HTTP Sender. Single-hop HTTP proxy requests are supported, as well as single-hop layered tunneling via CONNECT.
MIRTH-3302: Added the request URI and the protocol (e.g. "HTTP/1.1") as source map variables for the HTTP Listener. The difference between the URI and URL is that the URI is the actual _resource_ specified in the method line (first line of the request). However the URL represents the _location_ the request is targeting, and is dynamically built up by Jetty using the scheme, server name, port, and URI (so the URL always contains the URI). Also, added calls to StringUtils.trimToEmpty to handle possible null values.
MIRTH-3340: The HTTP Listener now validates the request URL returned from Jetty, and builds it up manually instead if it was invalid.