Move over, Silicon Valley. America has a new startup capital, according to a non-profit organization that studies startup trends throughout the U.S. So which city is currently home to the most startup activity in the U.S.?That honor goes to Austin, Texas. The rankings were compiled as part of the Kauffman Index, an in-depth measure of startup activity issued each year by the Ewing Marion Kauffman Foundation.Silicon Valley, which was #1 last year, fell all the way to #3 in the 2015 rankings. Miami now finds itself in the #2 spot in the Kauffman Index: The rate of new entrepreneurs,...