Remove wait for reboot when open() fails

The while(1) that used to be in open() simply hangs the Arduino sketch
on an infinite loop. If the WiFly card is rebooting, it's not bringing
the Arduino along for the ride, so it's pointless to wait for a reset
that's never coming. open() simply returns false now to indicate that it
was unable to open a connection.
Update to Pusher protocol version 6

The only change is to add an explicit protocol=6 URL argument when
connecting to Pusher, so the Pusher system doesn't assume we're using a
deprecated version of the javascript library. The Arduino library
reports itself as the js library, which formerly would result in Pusher
inserting the protocol version for us. This is no longer the case, so
protocol is now stated up front during the connection.