- Replace top layer with inline editor
- Make keypad and keyboard available for TextAreaMath

1. Check if an alias is present, so that the constructor creates one.
2. Only register the value IDs, when creating a valid element. Invalid 
elements generate and register IDs in the constructor (else path).

This method is the same for all elements and can be implemented in the 
parent.

The default value of the child class overrides the value set by the 
parent constructor.

- Image
- Hotspot-Image
- Audio
- Video
- Geometry
- DragNDropValueObject (imgFileName, audioFileName)
- LikertRowElement (imgFileName, audioFileName)

Table children do not have some properties, like position.

Javascript truthiness...

This fixes Tables which houses elements without dimensions.

The default value overwrites the value set in the parent constructor 
(Javascript...). Therefore the value needs to be intialized explicitly 
after the parent constructor has run.

#659

Separating code changes is rather hard right now, so there is a lot of stuff that is part of this commit that should not. Details below.

- All elements have static fields that holds their title and icon. This way dynamic lists can be built (for example for delete dialog) which show title and icon for all elements. ALso icons and names can be changed in one place.
- Template-Tab has been added. This should have templates to help creating groups of ui elements. This is work in progress and there are actually no templates yet. So this will change or even be removed in the future. This is mostly UI, the code is "TODO".
- Refactoring and improvement for delete and reference dialogs
- Delete logic refactored for elements, sections and pages. There are no longer different dialogs when references are found, but instead one dialog that can do both.

#635

#552

#618

- Prevent input of 'Dead' keys

(which is the height of a single item)

#525

- and AnswerSchemeValue with VariableValue