The OnePlus 3T has arrived, but in the process it's managed to kill the original OnePlus 3.That's not necessarily a bad thing as the 3T boasts a bigger battery, better selfie snapper and a more powerful processor - that is until you look the price.At $439 (£399, around AU$580)  the OnPlus 3T is $40 (£70) more expensive than its now discontinued sibling...