change page size for lastfm recent track fetch to 50
change page size for lastfm recent track fetch to 50

so empty page errors will have a smaller impact, hopefully...
http://www.last.fm/group/Last.fm+Web+Services/forum/21604/_/626352

also added some debug messages

opmuse/opmuse,opmuse/opmuse,opmuse/opmuse,opmuse/opmuse