Styling, Alignment titles, Empty choices, Categories, Callout, Image

* Styling: Colorzen only sets the border-style and border-color, but no
longer the border-width
* Styling: Fontsize is applied to span's too, not just p's
* Fixed alignment of titles
* Fixed empty values used in dropdownlists (resulted in "0" values
instead)
* Added additional font-sizes and image border widths
* Adding and removing categories happens in generic popup instead of on
postwizard/page template
* Fixed bug in categories editor (removing/adding)
* More properties use dropdownitems
* Callout widget now has configurable title font sizes
* Fixed image widget shadow