Battle of the blues Recently,  I spoke with retired NYPD Detective Tom Smith , who was on the Joint Terrorism Task Force, three decades with the NYPD, specialist on narcotics and gang warfare. I asked him about this snowball incident in Washington Square Park last week — people pelting cops — what should we do if comes more snow and more hooligans? Smith: “NYPD leadership gets in front of a camera. Says I want 20 people arrested on the scene. Cops can not be assaulted. Someone’s calling