Add of "modifier" hook, migration of charset plugin to new API, SIGHUP signal catched (reload all config files), better config files reloading

src/plugins/logger/logger.c

@@ -659,8 +659,11 @@ weechat_plugin_init (struct t_weechat_plugin *plugin)
  */
 
 int
-weechat_plugin_end ()
+weechat_plugin_end (struct t_weechat_plugin *plugin)
 {
+    /* make C compiler happy */
+    (void) plugin;
+    
     logger_stop_all ();
     
     return WEECHAT_RC_OK;