Singer/songwriter Keller Williams isn’t used to sharing the stage with other musicians. He usually prefers to play all the instruments himself, a one-man-band of stage bravado and showmanship who carries himself with the sort of confidence and affability that has earned him a reputation as one of the more unaffected guys in his business. On his latest release and ninth studio album, dream (SCI Fidelity Records), Williams briefly departed from his established solo style and recruited some of the finest jam band all-stars as guests on nearly every track. He hits the road with a live band for the dream tour circuit, stopping by the Town Ballroom next Thursday night (Feb. 22) for an all-ages show at 8pm