add class “reset_padding” for resetting panels

• often a accordion panel needs no padding, f.e. for including list-widget contents
  so just add this class to reset the default behaviour

resolved conflict:
Conflicts:
	lib/stylus_includes/widget/dialog.styl
move error_display styles

• in order to be available in all contexts
• cleanup

Conflicts resolved:
	web/css/admin/admin-ui.css
	web/css/widget/widget.css