Remove sortable element data from map. (#903)
Remove sortable element data from map. (#903)

* Remove sortable element data from map.

On destroy we need to remove the elements from stores map.
Otherwise if the elements are removed from the DOM, the element references will be available here, which will prevent the GC operation.
https://docs.microsoft.com/en-us/microsoft-edge/devtools-guide-chromium/memory-problems/dom-leaks

* fix and simplification

Co-authored-by: Lukas Oppermann <8c9caf7130cba3d4d3399d4bff1763e3c5a417ce@github.com>
lukasoppermann/html5sortable,lukasoppermann/html5sortable,lukasoppermann/html5sortable