We conclude our seven weeks of Get Back (with more to come soon enough) live on a London rooftop.     It would soon enough become a golden age for lawyers (although none with a legal bent ever went broke at Savile Row), but right here, right now (well, 53 years ago), it was four young men singing for the world without the aid of wine, bowties or black slip-ons [size 8].    Oh, yeah, there was also day 22.