GameRuleLogic methods should be public

[SKoschnicke]

They are now private, but they should be usable by the pupils and this breaks the GUI project which also uses validateShape and validateSetMove.

[anarchuser]

Which methods exactly?
I tried to make those methods private that don't make sense to use outside.
validateSetMove should be replaced with isValidSetMove which returns a Boolean instead of throwing up.

validateShape is implicitly checked in validateSetMove; does it make sense to have separately or do we rather want something like getValidShapes?