[TYPO3-50-general] Package Key Guidelines

[Sebastian Kurfuerst]

Hey,
> ^[A-Z][a-zA-Z0-9_]*$
Whoops, you are right, I already implemented it like this, but forgot to 
add the * here :-)
> But this RegEx matches faulty package keys like
>
> "F3_____foo"
That's true. I am not even sure if we really allow underscores? That's 
why I asked here.

Greets,
Sebastian