Overview: 2012/04/16 Headlines: Afghan Militants Stage 18-Hour Assault on Kabul; U.N. to Send Observers to Monitor Syria Ceasefire; Breivik Admits Killing 77 in Norwegian Massacre, Claims Self-Defense; Iran Nuke Talks Described as "Constructive and Useful"; Israel Disrupts "Flytilla"; Dozens of Pro-Palestinians Detained; Hate Crime Charges Filed in Tulsa Shooting Spree; Romney to NRA: "I Will Protect the Second Amendment"; "King of Bollywood" Detained Again at U.S. Airport; Bahrain Activists Protest Formula 1 Grand Prix Race; Ex-Argentine Dictator Acknowledges Deaths, Disappearances; Israeli Officer Suspended for Assaulting Pro-Palestinian Activist; Rep. Ed Towns Opts Not to Seek Re-election; 100 Tornadoes Hit Midwest; Five Killed; Heat Warning Issued Ahead of Boston Marathon;$