lists: extracting the list classes into own module
lists: introducing new list prototype (and hooking it up)
list: MorphList>>moveItemToIndex and MorphList>>find fix
lists: MorphList -- submorphs of list item morphs can have the flag
`hasOwnListItemBehavior` set to true. With that they will be able to handle
events themselves. Usful e.g. to embed a button inside a list element.
list: testMoveItemToIndex for MorphList
morphlist: enable menus
morphlist: clikcing on a selected item by default does not deselect it (enable this behavior with list.allowDeselectClick = true -- this should actually go inside a methods / config object!)
morphlist: keep selected style of list items on list update
morphlist: arrow keys up/down to navigate list
lists: buildSPec compatibility for MorphList