Fix #270: on iOS, List doesn't scroll correctly when it is inside a deli...

Set position:absolute, width:100% and height:100% on List's inner node => The List is no longer sized by its children
Set width:100% and height:100% as default on List => The List's parent height must be defined, see List.md
> As far I know natural height was already not supported see: #327

I don't know on what is #327 based, but at least with code such 
deliteful/samples/list/listBox-singleSelection-markAfter.html or deliteful/tests/functional/list/listbox-mark-2.html do seem to get their natural height (in the 0.3.0 release or in master).