Added onIndexChangeListener call when thumbs are moved as a result of bar touch.
Added onIndexChangeListener call when thumbs are moved as a result of bar touch.

finn-no/range-bar,hgl888/range-bar,dotfeng/range-bar,MeetMe/range-bar,jayeshthadani/RangeBar-Singlethumb,jtyang/material-range-bar,simple88/material-range-bar,jaohoang/range-bar,rameshvoltella/range-bar,java02014/range-bar,MaTriXy/material-range-bar,xiaoshi316/material-range-bar,SinnerSchraderMobileMirrors/range-bar,Harirexzeon/range-bar,yushiwo/range-bar,techery/material-range-bar,hide92795/material-range-bar,vpratfr/material-range-bar,oli107/material-range-bar,ultraon/material-range-bar