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

#548

Was completely broken: not showing at all in Editor, not clickable in 
Player.

Removed pipe 'aspectInputBackgroundColor'. Replaced by more elegant 
solution via inherited background-color.

THis component was still somewhat broken after the Material update.

#541

#545

#547

The inclusion of svg icons via the src parameter of an image tag
is prohibited in the test centre for security reasons

#538

The CSS selector for what the element to color changed (most likely with 
the Angular Material update). Also a lower z-index is needed to not 
cover the text.

#534

#536

- Remove all Roboto files

Since there is just one font, this setting can be safely ignored. This 
is easier than sanitizing all elements.

#513

#499
- Problem was due to changes in the latest minor material update

#533
- Remove unnecessary and wrong setting of underline property

#531

#532
- Replace the global label identifier

#535