This commit applies the new method `Terminated`. A side effect from
using this method is, we can now save one query `fetchPayment` inside
`FetchInFlightPayments`.
The routing package implements authentication+validation of channel
announcements, pruning of the channel graph, path finding within the network,
sending outgoing payments into the network and synchronizing new peers to our
channel graph state.
Installation and Updating
$ go get -u github.com/lightningnetwork/lnd/routing