For those of a certain age, it may be hard to believe that the Vans Warped Tour -- which reaches the Nikon at Jones Beach Theater Saturday, July 12, 2014 -- is celebrating its 20th consecutive summer in business. This year's mega-gathering of rock bands promises to be much like the 19 previous ones in its stylistic orientation toward youth (in other words, expect the music to be loud, hard and fast). But two decades on, a whole generation of performers and fans has grown up with the Warped Tour and can see it from a wider perspective.