By TESSA JAMANDRE HEARINGS on the Maguindanao massacre resumed Wednesday, the first under the Aquino government, with former Datu Unsay Mayor Andal Ampatuan Jr. and 16 other suspects pleading not guilty to the murder of the 57th victim, UNTV journalist Victor Nunez. Ampatuan, the alleged mastermind, and the other suspects, mostly police officers, were each