Update the UI for the scanner fragment

• Add a modal message for 0 devices showing
• Show the state of the connection next to every device

New 'scanning' screen, which shows when 0 devices are seen:

Status indicators for each device:

(either 'NOT BONDED', 'BONDING...' or 'BONDED', The lattermost is bold and has green text)

CC @Anon: @rahix wants this merged :)