- Remove the delay when opening the math keyboard in favor of an
explicit check

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

- to prepare markable support for text as compound children

#652

#628

#606

#608

- Toggling of keyboard and keypad are now async
- Keyboard and keypad animations are disabled for a short period of time

- Input field manipulation moves from service methods to new
  TextInputGroupDirective

- Not defined intersectionDetector leads to error

- InViewDetectionDirective determines the container itself
  as the previous binding returned an undefined value

- Resolve the conflict between the browser behaviour in concat scroll
  snap mode and the scroll button with delays
- Add space at the bottom of each page to ensure that the user
  can reach every element

- add padding
- add stopping on every page
- change selected index recognition

- Replace throwing Errors with InstantiationErors in unit, page and
  section in strictInstantiation mode

#547

#397