- FloatingMarkingBarComponent no longer has the elementModel property

- Error was raised when loading a second unit. It was caused by the
binding of the UnitStateService to the UnitMenuComponent

- rename variables, methods and properties
- reduce attributes for methods
- split code in sun methods

- remove prefix 'on'
- split methods

- Remove prefix 'on'

- Remove prefix 'on'

- Rename methods with prefix 'on'

SectionVisibilityHandlingDirective now controls the visibility of
sections that depend on an audio or video

Elements read as classes were overwritten by the plain objects passed to 
the constructors.

This is to convey a successful operation.

This way elements can handle their logic themselves without having to
rely on outside utility classes.

Also restructure files in common in a more logical way.