This is to avoid circle imports.

There is now a default method working the same as before. But elements 
(likert for now) can overwrite it and add some logic for specific 
properties.

Also add corresponding UnitService methods.

Remove warning for used-before-defined.

* Background: white
* Fontsize: x-large

Make sure that selection start is smaller than selection end

Before the defaults were simply set on any field regardless of the 
passed object.

The defaults were always overwriting the apssed values (if existing).

The main components are right at top level and the directories below
mimic the data structure (unit->page->section).
The toolbar is only used in dev mode and does not belong directly to the
unit view.
The TextEditor is a complex component and deserves it's own directory
even though it is used within the unit-view. Might be refactored to its
own module later.

The new elements now correctly set their own dynamicPositioning 
parameter to the setting of it's parent section.

Customized margins for paragraph elements.

This is now done via listener directly on the element overlay. The 
overlay's div is made selectable with 'tabindex'. Then the key event is 
caught and delete logic started. The actual logic did not change and 
still deletes all selected elements not just the one catching the delete 
key event.

- This helps getting rid of annoying element interaction and solves some
  selection issues (for example double clicking text elements to bring
  up the editor). While creating units, the placement and properties of
  the elements are important and not interacting with the elements.
  This is what the preview/player is for.
- This may also help with detecting selection for the Delete-key logic.

Mistake while merging earlier.