FRANCOIS MURPHY  AUSTRIAN police raided 18 properties and arrested 14 people in a massive dragnet on Tuesday, after a gunman identified as a convicted jihadist killed four people in a rampage in the centre of Vienna overnight. The gunman, who was killed by police minutes after opening fire on crowded bars, had been released from jail less than a year ago. An elderly man and woman, a young passer-by and a waitress were killed, and 22 people including a policeman were wounded, Interior Minister Karl Nehammer told a news conference. Vienna's mayor said three people were still in critical condition.…