TODO

* The widget need a way to get the ascent/descent for a string (not 
  all the characters in the font), to get the dialog a bit nicer.

* When the GTK_CALENDAR_NO_MONTH_CHANGE flag is set, the arrows for
  stepping the month/year should be hidden.

* Font changes should be done via GtkStyles, _set_font should be
  removed when this is done.

* There should be a way to change the colors. (GtkStyle)

* The widget should be nicely resizeable vertical to.

