Define a way how a CMP should handle unknown/unsupported commands

[janwinkler]

If a section introduces new commands but a CMP does not support them, how should the CMP react when the command is called?

Todo:
We should add wording/clarification on how CMPs should react in this case.

Suggestion:
Every command that is introduced in the future, MUST always have a "success: boolean" parameter as SECOND paramater of the callback function. If the CMP processes the command and finds that it does not understand it, it shall then call the callback with second parameter set to false in order to indicate an error.