Fix PHP incompatibilities in XMPPHP

Fix PHP incompatibilities in XMPPHP

This fixes the following to errors in XMPPHP:

Stack trace:
0 [internal function]: XMPPHP_XMLStream->endXML(Resource id 150, 'STREAM:FEATURES')
1 /var/vhosts/example.org/plugins/Xmpp/extlib/XMPPHP/XMLStream.php(420): xml_parse(Resource id 150, '<?xml version='...', false)
2 /var/vhosts/example.org/plugins/Xmpp/extlib/XMPPHP/XMLStream.php(471): XMPPHP_XMLStream->__process()
3 /var/vhosts/example.org/plugins/Xmpp/lib/xmppmanager.php(165): XMPPHP_XMLStream->processUntil(Array)
4 /var/vhosts/example.org/plugins/Xmpp/lib/xmppmanager.php(49): XmppManager->connect()
5 /var/vhosts/example.org/lib/iomaster.php(248): XmppManager->start(Object(ImMaster))
6 /var/vhosts/example.org/lib/iomaster.php(111): IoMaster->start()
7 /var/vhosts/example.org/scripts/imdaemon.php(58): IoMaster->service()
8 /var/vhosts/example.org/lib/spawningdaemon.php(189): ImDaemon->runThread()
 in /var/vhosts/example.org/plugins/Xmpp/extlib/XMPPHP/XMLStream.php on line 567
PHP Fatal error:  Uncaught Error: Function name must be a string in /var/vhosts/example.org/plugins/Xmpp/extlib/XMPPHP/XMLStream.php:567

PHP Fatal error:  Uncaught Error: Call to undefined function split() in /var/vhosts/example.org/plugins/Xmpp/extlib/XMPPHP/XMLStream.php:266
Stack trace:
0 /var/vhosts/example.org/plugins/Xmpp/extlib/XMPPHP/XMPP.php(129): XMPPHP_XMLStream->addXPathHandler('{http://etherx....', 'features_handle...')
1 /var/vhosts/example.org/plugins/Xmpp/lib/xmppmanager.php(145): XMPPHP_XMPP->__construct('geekplace.eu', 5222, 'gnusocial', 'U^k&l5fV53duGy', 'gnusocial', 'geekplace.eu', false, NULL)
2 /var/vhosts/example.org/plugins/Xmpp/lib/xmppmanager.php(49): XmppManager->connect()
3 /var/vhosts/example.org/lib/iomaster.php(248): XmppManager->start(Object(ImMaster))
4 /var/vhosts/example.org/lib/iomaster.php(111): IoMaster->start()
5 /var/vhosts/example.org/scripts/imdaemon.php(58): IoMaster->service()
6 /var/vhosts/example.org/lib/spawningdaemon.php(189): ImDaemon->runThread()
7 /var/vhosts/example.org/lib/spawningdaemon.php(118): SpawningDaemon->initAndRunChild(1 in /var/vhosts/example.org/plugins/Xmpp/extlib/XMPPHP/XMLStream.php on line 266