This is a free operation type that does not render much.

#590

#588

This holds variable names, taken from the GeoGebra applet, and uses 
those variable values in the value. This makes result analysis easier.

#579

An error was made in the last release. Now the numbers are correct.

#574

#558

#559

The directive for dynamic backgroudn color was outdated. Directive is 
removed and problem is solved via CSS custom variable.

#561

#449

- position
- label
- icon

- Replace throwing Errors with InstantiationErors in unit, page and
  section in strictInstantiation mode

#547

#513

- TextAreaElement, TextFieldElement, TextFieldSimpleElement,
  SpellCorrectElement:
  - remove property: softwareKeyboardShowFrench
  - new property: addInputAssistanceToKeyboard

#456

- Add Property "hasAutoHeight"
- Add Directive AutoHeight

- crossOutChecked adds line-through styling if checked. This is used in 
Cloze texts to cross out words.
- This means Checkbox is no longer a PositionedElement and does not 
validate PositionProperties