Over 17,000 runners competed yesterday in the Marine Corps Marathon in balmy weather with temperatures in the 70s. Ethiopian Retta Feyissa won the men’s competition, and Arlingotn’s Mary Kate Bailey became the first active duty Marine to win the women’s race since 1979. Race officials told the Post the warm weather sent 45 participants to area hospitals for dehydration. Three members of the DCist family were at the race in some capacity: Catherine and Hemal…