Amazon isn't shy about wanting to own as much of the Kindle Fire's software experience as it can, which creates a challenge when implementing voice search -- the company can't just re-skin Google Now and call it a day. The next-quickest alternative is to buy a company wholesale, and TechCrunch has evidence that Amazon may have gone that route through a very stealthy acquisition of Evi, best known for its eponymous personal assistant app. While neither side has publicly commented on the deal,
