add option to read (online) xmltv epg

Origin commit data
------------------
Commit: 8ad9f2e35c
Author: TangoCash <eric@loxat.de>
Date: 2018-09-01 (Sat, 01 Sep 2018)

lib/sectionsdclient/sectionsdMsg.h

@@ -67,6 +67,8 @@ struct sectionsd
 
                 setConfig,                      // commandSetConfig
 
+                readSIfromIPTVXML,              // commandReadSIfromIPTVXML
+
                 numberOfCommands        // <- no actual command, end of command marker
         };