The opening of Spoke Wine Bar in Somerville late last month continued the increasingly fine food and drink-centric neighborhood’s expansion. In other words, Davis Square just got a little Davis Squarier. It’s a welcome addition. The space, with 12 tables brushing up against a 10-seater bar that sweeps back toward a small open kitchen, is a little joint that thinks big in its sourcing of unique wines and a full, dynamic bar program.