List: Fixed invalid context execution for "itemFactory"

The "listItemFactory" and "itemFactory" functions that can be
overridden when the view is created now always run within the context
of the view, meaning "this" is the view.
View: fixed invalid check on loadingclass to set data and scroll

The bug is a mix between old code and the result of last merge.
There should not be any link between the fact that the options
specifcy a "loadingClass" and the fact that "options.data" get
preserved in the view and that the scroller gets properly initialized.