Merge branch 'v0.8'

* v0.8:
  Don't leak writer and index goroutines on close
  Clean up protocol locking and closing
  Send initial index in batches
  Always send initial index, even if empty (ref #344)
  Simplify locking in protocol.Index
  Protocol state machine on receiving side
  Log client version on connect
  Handle query parameters in UPnP control URL (fixes #211)
  Avoid deadlock during initial scan (fixes #389)
  Add temporary debug logging for #344 (revert later)
  Tone down UPnP not found message (fixes #406)

cmd/syncthing/main.go

@@ -483,7 +483,10 @@ func setupUPnP(r rand.Source) int {
 					l.Warnln("Failed to create UPnP port mapping")
 				}
 			} else {
-				l.Infof("No UPnP IGD device found, no port mapping created (%v)", err)
+				l.Infof("No UPnP gateway detected")
+				if debugNet {
+					l.Debugf("UPnP: %v", err)
+				}
 			}
 		}
 	} else {