No he didn't, it clearly did not say "Mylo Xyloto'. When you listen to it carefully, the first letter sounds like an 'A' . As he always does during the 'Fix you' song, he would dedicate it to someone and in this case maybe somebody on the side stage and to me it sounds like 'to Alex and Martha' (maybe?!). Anyway, i think people are just reading too much into this 'Mylo Xyloto' thing and just want to hear what they want to hear..