TWEEN idol Justin Bieber is Twittering furious after his hat was stolen and his mother knocked over as 500 fans mobbed him in New Zealand. Bieber has gone on Twitter today asking his leagues of zealous teenage fans to show a little restraint following the Bieber-fever frenzy in the wake of his Australian and NZ appearances. Authorities had braced themselves for Bieber-mania by appointing extra security at Auckland Airport and his hotel but within hours of arriving in NZ, the 16-year-old pop sensation took to his mega-popular Twitter account to ask fans to stay under control. “Finally got to New...