Add device inputs to webpage
Add device inputs to webpage

All current devices now render an element on the webpage.  When the user
interacts with the element, the element sends events and update the vrpn
server live.  When devices are changed on different webpage clients the
webpage updates live correctly.

Laremere/vrpn-webapp,Laremere/vrpn-webapp,Laremere/vrpn-webapp,Laremere/vrpn-webapp