After more than five years, Kickstarter users who backed the Sixense STEM — an eagerly anticipated, long-delayed virtual reality motion controller — are all being offered refunds, as Sixense abandons its original plan for a mass-market device. Sixense is sending its 2,383 original backers a message today, and it’s also offering refunds to people who preordered the STEM system after the 2013 campaign closed. It will continue to produce hardware for businesses, which is a...