cells-by-row asset in test
refactor updateSortData: ref #602

+ add Isotope._getSorters()
+ add Isotope._updateItemsSortData
+ change updateSortData() to public method only
add Isotope.sortDataParsers

Allows for user to add custom parsers fort getSortData shortcut strings
refactor _getFilterTest
add Isotope._noTransition; bit o' refactor
insert only transitions reveal for new items

requires Outlayer that respects item.isLayoutInstant