Updates README with npm install instructions.
Updates README with npm install instructions.

patricklodder/node-xmlrpc,MiniGod/node-gbxremote,hobbyquaker/homematic-xmlrpc,baalexander/node-xmlrpc,xmlrpc-js/xmlrpc-marshalling,Growmies/node-xmlrpc,AfterShip/node-xmlrpc,bolster/node-xmlrpc