You may still think of the Winklevoss twins as those guys who claimed to have invented Facebook, but they've just taken a big step toward making their names in the digital currency business. The two have filed a New York trust application necessary for them to launch their Gemini bitcoin exchange. The move won't put Gemini on the same level as a bank if it's approved, but it will let the exchange accept deposits, issue loans and serve as an agent for government institutions.