TODO - our view etc functions don't have our shared key, find a good way
to get this. A possible solution is just to lazily store it so that we
don't need to call lnd/create a session every time we want to restore
it.
This commit bumps the current protocol version and integrates htlc v2
with loop in/out for new swaps, while keeping htlc v1 for any pending
swaps with previous protocol versions.