Added support for CheckBoxes/Tristate CheckBoxes to LabeledInputField, needed for Eigendiagnosen

Added support for CheckBoxes/Tristate CheckBoxes to LabeledInputField.
This one will be used for the new version or Eigendiagnosen.
Added some documentation for the methods how it should actually be - makes it much simpler for newbies...

Many other types are not implemented which would be more than just useful. This way we can let look our AutoForms much more professional.
I already have implemented some others but that's not yet clean. Still thinking about the best/consistent way...

Gruss, Harry