should fix#618 and #597
oldIndex was changed first by with the item being dragged, but also by the drag event of the parent (which should be avoided when we are not using the drag-handle)
This event will fire when an element is chosen, and is particularly
useful for providing the user with a visual, auditory or tactile indication,
in case a delay was enabled.
An attempt to implement the "distance" option (like http://api.jqueryui.com/sortable/#option-distance).
This is useful when your sortable element is also clickable. This prevents the drag to begin due to a micro-movement when you click.
when nesting Sortable's, we're not interested in this error:
"HierarchyRequestError: Failed to execute 'appendChild' on 'Node': The new child element contains the parent."
As done in the other place where `dataTransfer` is used.
This is to support fake html5 drag and drop events, where `dataTransfer` is not accessible. Use case: Selenium testing with ePages-de/chromedriver-html5-dragdrop
removed the default behaviour to append the cloned Element to the body.
now the cloned Element gets added in the same parent, with the addition
of the class defined in options.fallbackClass.
added the possibility to change the fallback class.
added the possibility to decide wheter the fallback should be cloned
into the same parent or to the document's body.
modified the private _onMove prototype, so it calls events on it's
source Element like it's sibling function _dispatchEvent
added the handleMove, which listens to the onMove events to the react
mixin
added forcePolyfill option.
forcePolyfill is made to make cross-browser testing more easy.
forcePolyfill provides a reliable, consistent cross-browser Solution for
Sortable.
forcePolyfill gives us the possibility to change the way "dragged items"
lok like.