EXCLUSIVE: In what is believed to be the biggest sale so far this season, ABC has landed Doomsday, a thriller drama from producer Carol Mendelsohn (CSI), writers Mark Bianculli & VJ Boyd (Justified) and Sony TV. I hear ABC got the project in a 3-network bidding by giving it a pilot production commitment that has series penalty behind it. Written by Bianculli and Boyd, Doomsday starts in the aftermath of 9/11 when the US government institutes a secret think tank featuring…