Add Dispenser Behavior API

This API allows plugins to directly interact with the ```IDispenseBehavior``` registry in ```net.minecraft.server.BlockDispenser```. This allows new functionalities with dispensers, which cannot be achieved without kludgey code with BlockDispenseEvent. I have tested this API to make sure it is both safe and prevents crashes due to plugin code. I can provide my test plugin if desired. Fun use cases: auto-block-breakers, dispensing food to feed a player automatically, spawning lightning, and of course removing unwanted dispenser behaviors.