list api change

Marc,

Be advised, the list is now multi-selection capable and therefor the
selected methods have been replaced with selection() which returns a
vector<list_item::ptr> of the selected items.

Thought you would want to know in case you are using list at work.

Spinner is likely to be changing in the near future as well, I am
starting to think that it shouldn't derive from list.  (selection
doesn't make any since for example, at least not if it returns a
vector).

Darren