Research firm Gartner has released its latest forecasts for tablet sales through 2015, which predict that Apple will still hold a 47.1 percent of the market in 2015, on sales of over 135 million iPads. “Seeing the response from both consumers and enterprises to the iPad, many vendors are trying to compete by first delivering on hardware and then trying to leverage the platform ecosystem,” said Carolina Milanesi, research vice president at Gartner.…