AUSTIN — The Texas Tribune Festival here over the weekend was friendly territory for Democratic U.S. Senate candidate James Talarico. The First Baptist Church downtown was filled to capacity for a Talarico visit, and if the crowd were any more enthusiastic, you’d have thought it was the 1950s and Elvis Presley had showed up. But it’s hard to blame them; for the first time in a long while, Texas Democrats have persuasive reasons to think their guy will win.