Zero optional repeats should not be allowed

[zimmski]

Zero optional repeats like

START = *("a" | )

should not be allowed since this opens problems with the internal parser and therefore with the reduction process. The Problem is that this will result to the token Graph Repeat -> Optional -> String, which means that Repeat can repeat deactivated optionals. Meaning that the input "" could be not only zero repetitions but also a million of it.

[zimmski]

EVERY repeat with just an optional should not be allowed!