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
Also about the sizing issue in the test, yes we know that this was discussed (#270) on the issue right? You need to have 100% to all parents? What is new to this PR compare to issue discussion?

Quotation from #270:

> Unfortunately, using position:absolute; width: 100%; height: 100% on the container node forces the user to set a height in pixels on the List or an height an all ancestors of the List (by including defaultapp.css for example).