WebSocket: initial websocket support + utilities

closes: #166

This patch provides an initial implementation for websocket support for
paho. For the websocket specification see RFC 6455.  The purpose of this
patch is to allow connnecting to an MQTT broker listening on a websocket
port (typically 80 [HTTP] or 443 [HTTPS]) to be able to communicate with
a client using the paho library.  Using websockets to communicate increases
the packet overhead both sending and receiving as well as additional setup
and ping packets.  However, using websockets allows for communications on
standard HTTP/HTTPS ports which are generally already configured by
firewalls to allow outside communications.

To use websockets, prefix the connection URI with either: "ws://" or
"wss://" for either websockets or secure websockets, repectfully.

Signed-off-by: Keith Holman <keith.holman@windriver.com>