Violinist Jennifer Koh bounds from one brilliant concert to another sharing her artistry and admiration for the teachers who groomed her and the composers who inspire her. No stranger to Washington, she completes her Bach and Beyond series for Strathmore’s Music in the Mansion concerts this week and will continue her tribute to Bach two weeks hence at the Kennedy Center in “Two x Four” with violinist Jaime Laredo, her former teacher at Curtis Institute of Music in Philadelphia.