Move Linux client & common packages into a public repo.

ipn/doc.go

@@ -0,0 +1,11 @@
+// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package ipn implements the interactions between the Tailscale cloud
+// control plane and the local network stack.
+//
+// IPN is the abbreviated name for a Tailscale network. What's less
+// clear is what it's an abbreviation for: Identified Private Network?
+// IP Network? Internet Private Network? I Privately Network?
+package ipn