Build rv2.beta.20

Fixes #675 No disabled feature should log spam or crash anymore.

For developer: Deprecates the old usage of the AEItemDefinitions via the direct method access of * blocks() * parts() * items() * materials() and thus use the new re-direct via definitions(). All definitions are now initialized, no matter what. But SubItems, Items and Blocks are not registered, if by chance are disabled. - thatsIch