This way the value of the selection box is displayed initially

- Remove property dropListIDs
- Remove mousedown event

Otherwise, no elements can be dropped at this place

To detect if a custom form element was touched it is necessary to set a
custom tab index

... to create new references for the connectedTo array.

This version is unreleased and can be used.

Use the source list placeholderIndex instead of the index for the target 
list.

Chromium does not allow DOM manipulation on dragstart. Therefore add 
timeout.

Duplicate value objects without keeping the reference to the old object.

- Replace Material Droplist with native HTML events
- Remove simple-drop-list element; Cloze elements now use the normal 
DropList element
- Add example units

- Rewrite interface 'VopMetaData'
- Add parameter 'metadata' to VopReadyNotification

- TextAreaElement
- TextFieldElement
- TextFiledSimple
- SpellCorrectElement

- Replace type 'any' with 'unknown'

- This corresponds to the representation in the keypad
- Prepares further adjustments to the keypad

- Name the control keys of the keyboard like those of the keypad

- Use the VeroSubscriptionService as a pure communication service
- Do not contaminate the VeroSubscriptionService with holding data

- Add the new features from version 3.7.0
- Fix the entries from version 3.8.0

- Using the Geogebra method 'getBase64' is very resource intensive.

- Using scrollIntoView with target 'center' was not always reliable
  especially in FF

- The workarounds for ff with setTimeout are no longer necessary in the
  new version and have been removed
- Replace ChangeDetectorRef.detectChanges with setTimeout because the
  scroll button was not always reliably displayed at startup

This is necessary to avoid playing parts of audios and videos twice
when a unit is reloaded, since audios and videos send their playback
time only every 5 seconds when they are played back.

- Make sure that the textarea has been displayed once (AfterViewInit)
  before its dimensions change again

- The width of the border is no longer needed because
"box-sizing: border" is used
- Scaling of the inner triangle areas is replaced by the setting of 500%
 width and height to be able to fill the whole area of the obtuse
 triangles and at the same time not change the width of their borders