CFO_BODYSEQ_3buttons_arp missing lastNote

[kritzikratzi]

variable should be called lastNote, not lastKey in line 79:

https://github.com/jsr606/CFO/blob/master/CFO_BODYSEQ/Arduino/experimental/CFO_BODYSEQ_3buttons_arp/CFO_BODYSEQ_3buttons_arp.ino#L79