New York City Mayor Michael Bloomberg is holding a terrorism-related press conference tonight at 7:30 pm. NYPD Commissioner Ray Kelly and District Attorney Cy Vance will also be in attendance. This is a late breaking addition to Bloomberg's schedule — and the presence of Vance indicates there may have been some sort of arrest. Neither the Mayor's Office nor the NYPD are releasing any information prior to the press conference. UPDATE 6:24: NBC's Jesse Rodriguez tweets: WNBC: Terror suspect taken into custody yesterday; lone-wolf suspect was preparing a pipe bomb. UPDATE 6:28: The New York Times is reporting that the...