In this commit we introduce pruning of channel edges instead of channels.
Channel failures apply to a single direction and it is unnecessarily
restricting to prune both directions.
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
3ed16837e4
