* Add IntersectionService
* Add CompoundElementComponent as parent for LikertComponent
* Inject ElementRef to common ElementComponent
* Rename players' ElementComponent to ElementContainerComponent

* Remove FormService Injection
* Move FormService and form types to player
* Move interface ValueChangeElement to uI-element.ts
* Use interface InputElementValue instead of
string | number | boolean | null

* Add `InputElementValue` as type when needed

Should at least be in util folder. And since it is imilar functionality 
to the unit factory it is placed within.

Make sure that selection start is smaller than selection end

* Remove general (full) keyboard in layout component
* Implement French keyboard component

* When elements receive the focusin event, their status is changed to
`TOUCHED`
* Replace `this.form.valueChanges` subscription with
`this.unitStateService.unitStateElementCodeChanged` subscription

* Take over tasks of `UnitStateComponent`
* Manage property `unitStateElementCode`
* Removing the passing of the property `unitStateElementCode` by
the components

* Implement as draggable overlay
* Keyboard can be configured as 'mini' or 'full'

* Value and status of all elements are saved
* Move some Methods and Properties from FormService to UnitStateService

* `UnitState.dataparts` has property `elementCodes` property, which
stores status, value and id for FormElement
* When building a unit, the stored value is assigned to the element
when it is initiated
* Removed `UnitState.dataparts.pages`
* Removed methods initPages and addStoredValues

* Rename service to `KeyboardService`
* Replace the two fixed rows for upper and lower case letters
of the keyboard with a general row array
* Rename css classes, variables and methods

* After deleting validation component, element component is no
longer needed and is deleted
* Element overlay takes over the methods of element component

* Remove unnecessary styles
* Refactor case distinctions
* Improve styles of some elements

Refactor styles for elements and element overlays to achieve stretching
of dynamic sections when text areas are resized

Break up the code into smaller methods

* Increase height for textarea and textfield after adding new material
styles
* Remove position for validations

When elements are dynamically positioned there is no space below the elements

Required after changes in element components
(commit: 9e3c0613)

* Since always visible pages are removed from the order, form
arrays must be rearranged
* Refactor getter as properties in `PlayerStateComponent`. Getter
work like functions and are executed every time Angular change
detection runs.

* Create `FormGroups` without ids
* Add `FormArray` for elements

* Add section array to the form groups of the pages
* Remove unnecessary component factory from `SectionComponent`

Also refactor a lot of stuff belonging to this:
- You can edit the default values via properties panel
- All elements now again have a common parent directive. form elements
have a special parent for forms.