Multi List and List bug fixes

[cursork]

A customer is trying to utilise the List component in their app:

1. It is not possible to select anything in the list – double click on the List item does not work.
2. Style property does not work.
3. Impossible to select multiple items.
4. If the initial selection is on item 1, and then you press Shift key and click on the last (5th) item expecting to select all items, only 2 3 4 5 items are selected
5. Dragging the mouse It is possible to select a random area. Pic. 2.
6. xWG of SelItems does not return any real result: it is always the empty vector.

I've pushed a DemoList (provided by the customer) to the next branch of ewc.

It looks like the code should be easily modifiable to adapt to multiple selection given 'Style' = 'Multi'. While here, it'd be good to remove the use of localStorage when updating the SelItems code.