Add routine for checking possible standby (fixes #565)

cmd/syncthing/main.go

@@ -559,6 +559,8 @@ nextRepo:
 		}()
 	}
 
+	go standbyMonitor()
+
 	events.Default.Log(events.StartupComplete, nil)
 	go generateEvents()
 
@@ -1164,3 +1166,15 @@ func overrideGUIConfig(originalCfg config.GUIConfiguration, address, authenticat
 	}
 	return cfg
 }
+
+func standbyMonitor() {
+	now := time.Now()
+	for {
+		time.Sleep(10 * time.Second)
+		if time.Since(now) > 2*time.Minute {
+			l.Infoln("Paused state detected, possibly woke up from standby.")
+			restart()
+		}
+		now = time.Now()
+	}
+}