previousDragX
Merge branch 'master' of github.com:metafizzy/flickity
start on wraparound - clone and position before cells
add after clones
kinda working
add selectedWrapIndex for wrap-around
add wraparound logic in select, previous & next
refactor clone logic
add _getClosestResting, non-wrap-around logic
fix onresize bug for wrap-around
add percent positioning
add getPositionValue for percent positioning