Reduces the visibility of all fields to private and create setters/getters
when necessary. Exceptions are fields with GuiSync as these need to be
public.
Reduces the visibility of internal methods to private/protected/default when possible.
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.
The AE2 has in the contract that the item field in an IAEItemDefinition can be null due to the fact, if a special item is deactivated. This needs to be checked.
The base code was enhanced through Javadoc and split in responsibilities
