* Widget decorator v2, Container widget, TextArea option, Sheet title + icons

* Widget decorator v2: generic widget options are now explicitly set
using a method on a per widget basis. Generic options no longer show as
a seperate item (decorator), but instead are a wrapped set of options in
the popup of the widget.
* Added experimental 'Stack' widget, can be used to veritcally stack
widgets in a widget (turned off in extensions)
* TextArea option can now configure # of cols and rows, defaults to 50
cols and 15 rows
* Widgets now have sheet title + icon