Ellen Taaffe Zwilich: Symphony No. 5 Sarah Brady, flute; Gabriela Diaz, violin Boston Modern Orchestra Project, Gil Rose, Music Director BMOP/Sound 1098   Composer Ellen Taaffe Zwilich turned eighty-five in April, and one of the many celebrations of her life and work is a recording by Boston Modern Orchestra Project. Directed by Gil Rose and featuring flutist Sarah Brady and violinist Gabriela Diaz as concerto soloists, it is a generous program of her music. The centerpiece is Zwilich’s Symphony No. 5 (2008), a powerful four-movement work that combines traditional formal structure with a musical language of a more recent vintage.