A multi-instrumentalist and noted polymath, Cameron Lew (AKA Ginger Root) makes polished, DIY synth-pop, fused with alt-disco, boogie, soul and (as evidenced on the new single “No Problems”) Japanese city pop. Tapping into Ram-era Paul McCartney, with endearing and bright chord progressions and an orchestra of ambient synths, Kew builds a lively atmosphere on “No Problems,” waxing self-consciously about a …