From now on every integration must not rely on method stripping through
a coremod or @Optional. Notable example for a very good solution is IC2.
As consequence this drops all support for RF and mods must support on of
our supported energy types. At the time of writing, ForgeEnergy and
IC2/EU.
* Cleaned up unused Mod integrations other than for mods that are likely to be integrated soon.
* Introduced an easier Facade class to access mod integration abstractions (called Integrations).
* Removed the link between IntegrationType and integration abstraction. Integrations are now explicitly instantiated inside of IntegrationNode.
yueh