Make thread watcher keybinds handle case when thread watcher is disabled.

src/Miscellaneous/Keybinds.coffee

@@ -92,9 +92,10 @@ Keybinds =
           else
             return
       when Conf['Watch']
-        return unless thread
+        return unless ThreadWatcher.enabled and thread
         ThreadWatcher.toggle thread
       when Conf['Update thread watcher']
+        return unless ThreadWatcher.enabled
         ThreadWatcher.buttonFetchAll()
       # Images
       when Conf['Expand image']

src/Monitoring/ThreadWatcher.coffee

@@ -1,6 +1,6 @@
 ThreadWatcher =
   init: ->
-    return if !Conf['Thread Watcher']
+    return unless (@enabled = Conf['Thread Watcher'])
 
     @shortcut = sc = $.el 'a',
       id:   'watcher-link'