Mara Brock Akil, the acclaimed showrunner and executive producer, is set to make her debut as a novelist with “The Revelation of Dionne Daphne,” to be published June 30. The novel will be released by Storehouse Voices, an imprint of Crown Publishing. Known as the creator of such enduring series as UPN/CW’s “Girlfriends,” CW/BET’s “The Game,” BET’s “Being Mary Jane,” OWN’s “Love Is __” and Netflix’...