Longtime “Sunday Morning” viewers will recognize Eugenia Zukerman, the internationally-acclaimed flutist, who for more than 20 years covered the arts for this broadcast. But now, Zukerman is opening up to Rita Braver about her battle with Alzheimer’s, and how music, writing and humor are helping her cope, as she describes in her book, “Like Falling Through a Cloud: A Lyrical Memoir of Coping With Forgetfulness, Confusion, and a Dreaded Diagnosis.”