A Perth start-up is poised to open the virtual doors of its online Aussie casino, but founder Laurence Escalante believes exploiting a loophole in Facebook’s sweepstakes rules could be an even bigger money earner. Mr Escalante’s Virtual Gaming Worlds operates Chumba Casino, an online world where users play digital poker machines and card games for free, with no chance to win prizes. The ‘social casino’ makes money from dedicated users, who pay for things like extra credits and premium play. Chumba Casino exists solely as an app within Facebook, but Mr Escalante received a license from The Philippines in August…