Added world related events (tree_grow, world_load, world_unload, world_save).
Added some default methods in AbstractEvent.
Revert "Added some default methods in AbstractEvent."
Minor fixes related to the reverting.
Merge pull request #235 from King-Fisher/worlds

Added world related events (tree_grow, world_load, world_unload, world_save)
Added more verbose profiler points to server startup/reload
Merge origin/master
Fixed a bug with cron tasks.

Previously, the cron tasks weren't properly being unloaded when the scripts were recompiled. Now all cron tasks are cleared when the engine stops.
Minor change.
Firework meta now shows up in pinv.

set_pinv still does not accept the firework meta, but it can at least be read now. Making it work with set_pinv will be a more difficult task, and so will be completed at a later date.
Began TaskManager. Doesn't work yet.
Provide a cause if ItemMeta fails.
Support lore being a string in ItemMeta.
Firework meta data is now supported.

All methods that use the ObjectGenerator class will now implicitely support firework meta, including set_/pinv(). This fixes the issue where set_pinv(pinv()) would clear the player's firework data.
Made profiler info a bit more useful
Fetched from Upstream