This element has a list of string as editable options. Those strings 
form draggable elements which may be reordered or moved between 
different DropList elements.

Also refactor option change logic to allow any property not just the 
text property.

This includes a fix in the dispacker, which no more tries (and fails) to 
replace variable names.

It logically belongs there since it is no compound element and also 
needs to be near the other radio group.

Now correctly shows a dropdown instead of a text area.

This works similarly to the standard radio group, but has a fixed 
horizontal layout with images above the options.

When selecting the preset value, sometimes the string is empty and it is 
not possible to differentiate the options. Therefore an index is added 
making it possible to reliably select a value.

Use the status of each element

* Change the detection of the parent element to determine whether the
audio/video player is running in the aspect-editor or the aspect-player

* Add magnifier properties to `ImageElement`
* Set used value at `UnitStateService`
* Bypass parsing error of distpacker

Wait until a solution is found for the distpacker when parsing "'url('+ (image.src) + ')'".

Use flex to position image and text below one another. Don't use any 
image scaling setting. Now the images grow but don't shrink.

For testing purposes.

The whole panel tab was not correctly checking for value existence. Need 
to check for undefined not null.

Function was incorrectly returning after the first element.

There were some things missing when renaming questions/answers to 
rows/columns. Now everything is properly named.

* Show current and maximal runs in control bar

This function will be implemented differently.

* Refactor markable text
* Prevent multiple selections (feature is only supported in Firefox)

To not have the same name as likert rows and cause issues on the props 
panel.