Just two and a half weeks after Dr. Martin Luther King Jr.delivered his "I Have a Dream" speech, the 16th Street Baptist Church in Birmingham was bombed, injuring 22 and killing four little girls. Fifty years later, we're just beginning to learn about a "fifth girl" who made it out alive. WGBH News reporter Clennon King sat down with Sarah Collins Rudolph this morning to find out what brings her to Boston.