'Barking clown': Bloomberg fires back on Twitter after Trump taunts

* President calls former New York mayor ‘a loser’* Bloomberg says Trump is known as ‘a barking clown’ Donald Trump and his fellow billionaire and would-be presidential challenger, Mike Bloomberg, traded insults on Twitter on Thursday, with Trump dismissing the former New York mayor as a “loser” and Bloomberg describing him as a “barking clown”.Using a now-familiar line of attack that misstates Bloomberg’s 5ft 8in stature, Trump tweeted: &ldqu