[Ovmsdev] USSD

I'm about to start work on the USSD protocol we had previously discussed. Just a technical evaluation at the moment, to see if this is feasible. The www.openvehicles.com:6867 development server may go up+down quite frequently for the next month or so, as I try different things. If anyone is using that server for their car, I strongly recommend you switch to tmc.openvehicles.com:6867. Thanks, Mark.