Temporary fix to ping_flash2 problem (#87) by using api to generate pong

At least until a reliable central API can be set up, we can send a request to the spotlite server to generate the pong. Once we have an api up and running, it's just a matter of changing the url of the http request.
I'm getting: TypeError: Object # has no method 'sendCommand'
Bit of a fail at Javascript, but because the "this" referenced here isn't the Spotify class but the http.get class?