Can register/deregister RPC handlers on the MainLoop imperatively.

ccnode/node.py

@@ -243,6 +243,12 @@ class MainLoop(object):
         for tag in self.tag_db.pop(sub_id, {}).itervalues():
             tag.stop()
 
+    def reset_handler(self, name, handl):
+        self.rpc_handler[name] = handl
+
+    def remove_handler(self, name):
+        self.rpc_handler.pop(name, None)
+
     def register_plugin(self, plugin):
         # keep track of registered plugins
         if plugin in self.registered_plugins: