This solves the age-old issue of PlayerInteractEvent firing twice when a player clicks a block with an item in the hand.
API changes:
- Removed PlayerInteractEvent constants LEFT_CLICK_AIR, RIGHT_CLICK_AIR and PHYSICAL.
- PlayerInteractEvent no longer fires when the player right-clicks the air.
- Added new event PlayerItemUseEvent.
* Event handlers always handle subclass events. public static $handlerList no longer required.
* Removed $handlerList declarations
* HandlerList cleanup: Removed HandlerList->handlers and related bake methods
* Removed obsolete Event->getHandlers()
* EventPriority: Added fromString()
* PluginManager: throw exceptions on registering handlers with invalid priorities
This allows specifying a handler of `EntityDamageEvent` which will handle any instanceof it (as per current behaviour), AND also now allows specifying a handler specifically for `EntityDamageByEntityEvent`, which only handles `EntityDamageEvent`.
This was not previously possible due to limitations in the way handlers were registered.
Abstract events may not be handled unless they declare the `@allowHandle` PhpDoc tag.
