test: rename CT to harnessTest, ensure all RPC's get distinct timeouts

This commit slightly modifies the existing CT struct in order to
maintain consistency with code-style. As a result of the name change,
all references have also been renamed from `ct` to `t`.

The Error and Errorf methods have been removed in favor of forcing
everything to be reported via `Fatalf`. Additionally a new method
(ProcessErrors) has been introduced to the networkHarness class in
order to encapsulate the underlying channel.

htlcswitch.go

@@ -611,11 +611,14 @@ func (h *htlcSwitch) RegisterLink(p *peer, linkInfo *channeldb.ChannelSnapshot,
 	return h.htlcPlex
 }
 
-// unregisterLinkMsg is a message which requests the active ink be unregistered.
+// unregisterLinkMsg is a message which requests the active link be unregistered.
 type unregisterLinkMsg struct {
 	chanInterface [32]byte
 	chanPoint     *wire.OutPoint
 
+	// remoteID is the identity public key of the node we're removing the
+	// link between. The public key is expected to be serialized in
+	// compressed form.
 	// TODO(roasbeef): redo interface map
 	remoteID []byte