check keymap changes on startup;

--- a/src/Tools/jEdit/src/plugin.scala	Thu Sep 01 14:57:04 2016 +0200
+++ b/src/Tools/jEdit/src/plugin.scala	Thu Sep 01 14:57:36 2016 +0200
@@ -333,6 +333,8 @@
               "It is for testing only, not for production use.")
           }
 
+          Keymap_Merge.check_dialog()
+
           Session_Build.session_build(jEdit.getActiveView())
 
         case msg: BufferUpdate