John Caudwell thinks more billionaires should give away their fortunes like he plans to, after the super wealthy star pledges to donate more than 70% of his wealth. The Phones4U co-founder has signed up to The Giving Pledge, an ongoing and world commitment for anyone who signs up to donate more than half of their fortune to charity. The figure needs to be given away either before or after they die, or both. John Caudwell joins other billionaires who have pledged, including Elon Musk, Richard Branson and Mark Zuckerberg. He signed the pledge in 2013 and says he can’t understand why other billio…