multi: add README's for all sub-packages

routing/README.md

@@ -0,0 +1,19 @@
+routing
+=======
+
+[![Build Status](http://img.shields.io/travis/lightningnetwork/lnd.svg)]
+(https://travis-ci.org/lightningnetwork/lnd) 
+[![MIT licensed](https://img.shields.io/badge/license-MIT-blue.svg)]
+[![GoDoc](https://img.shields.io/badge/godoc-reference-blue.svg)]
+(http://godoc.org/github.com/lightningnetwork/lnd/routing)
+
+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
+
+```bash
+$ go get -u github.com/lightningnetwork/lnd/routing
+```