Import of on/off widgets and select widgets does nor work propperly.

I have been struggling with this for days. In one case an error was given (i do'nt remember witch), in an other (on/off widget) the imported value was always the "on" value.

I have rewritten the (small) function (optionwidgets.inc) such that ALL optionwidget types are processed correctly. (I think).
These are optionwidgets_buttons, optionwidgets_select and optionwidgets_onoff. I have taken into account if the widget is multi-select or single-select and the special case were the "off" value for an on/off widget is being imported.

I have tested this with:
on/off,
Buttons single-select,
Buttons multi-select,
Select single select,
Select multi-selec

Attach is file "optionwidgets.inc" with he new code.