Multipeer address discovery

Summary: Using MultiPeerConnectivity.framework, advertise a client's next receiving address as well as a randomly generate non-unique PeerID handle. In one new view controller, in a text box allow the user to set their PeerID for a short time to assist others in rationally determining which peer in their immediate vicinity is likely broadcasting the address they want to use. For security as one should have in dipping their toes into peer to peer network, peers never authorize a bidirectional binary session. Only advertising data is consumed & broadcast.
Show a tableview of available peers & addresses, and allow for easy flow into the payment screens.

SANITY MEASURE: The delegate of BRAmountViewController does not complete the transaction and submit it to the network. Can be trivially connected. Focus is on UI & functionality review.

Run the code on two iPhones with bluetooth turned on to see discovery & the (lame) UI in action.