That's not Mayella Ewell, Your Honor. If asked to choose a picture of actress Collin Wilcox-Paxton out of a lineup, most of you could not. But you wouldn't mistake her for Gregory Peck. Or would you? The actress, best known for her role as Mayella Ewell, the horrid, white trash fabulist whose bogus rape accusation against a black man forms the crux of the movie To Kill a Mockingbird, died this month at age 74. The Chronicle's online edition ran an Associated Press obituary along with the abov