AN EXPERIMENTAL TONE SETS JAMES SEWELL BALLET’S winter concert, the Ballet Works Project, apart from the rest of JSB’s season. A smaller stage (the intimate Southern, not the wide O’Shaughnessy), lower-budget costumes, and a variety of choreographers — Hijack (Kristin Van Loon and Arwen Wilder), Shannon Christie, and Nic Lincoln, in addition to James Sewell — all give the impression you’ve been invited to a…