Use store item in isItemEditable, isItemResizeEnabled & isItemMoveEnabled
Updated sample according to latest commit
Used cached store item instead of calling renderItemToItem

renderItemToItem is misused when called in another use case then
editing.
Use a cached store item. Will also helped non cached JsonRest stores use
case.
Fixed editing event non compliant with new policy (storeItem & item)
Added test case to check these onItemXxxxx events