- A suitable version was not available after update of Angular
- Reactivate test for valid pages

Most importantly remove the standalone switch and let the service always 
send postMessage, even when there is no surrounding application 
listening. This helps testability and has no downsides.

Also:
- Make methods static where applicable
- Remove useless variables and methods
- Improve variable initialisation (to allow undefined)

- This allows to assign a font to a text in MatFabButtons

Element margins and grid sizes now have a measure unit attached. The 
translation logic to merge unit and value are done via Pipe.

Media elements needs time to load and change the dimensions of the page

#441

Replace the assignment of the ElementComponent with the assignment of
a ElementComponent that will work in future versions of Angular

Displaying a message is task of the host
#398