Scroller: refactored throw duration and distance calculations to better match ios behavior (while still allowing old behavior that more closely matches android, if desired) based on research presented at http://ariya.ofilabs.com/2011/10/flick-list-with-its-momentum-scrolling-and-deceleration.html, scrollToPosition() and scrollToPageIndex() now default to durations matching a touch-based throw instead of 0 (since there are properties to programmatically update scroll position without animation, the old default of 0 didn't make sense). updated license to reflect the rewrite of scroller code that used to be based on third-party code.