Removes the improper way to set itself into a public static non-final variable.
Removes the direct access to the IntegrationRegistry from AppEng. Will be added at some later point somewhere else for non-singleton access.
Constructor is set to package private to enable possible construction from unit tests. Are current not runnable sind it is currently tied to the FML Loader instance.
Every Block had a call to its super, passing its own class.
This can easily be simulated by calling `this.getClass()` in the super class.
Also this was basically only used as using a name.
In the future it might be advisable to not use such methods,
since they are prone to refactoring.
