beaglebone: handle when preserved globals are not set
beaglebone: automatically run dashboard for Bacon Cape

http://beagleboard.org/static/freeboard/?dweetioname=<name-of-already-connected-board>

http://beagleboard.org/static/freeboard/?address=<ip-of-board-to-configure>

Right now, you have to look at the datasources to find out what the dweetioname is
for the next time you want to connect. Next task is to figure out how to get that to
display in the dashboard.