[Bleeding] Deprecate the pointless Potion.Tier enum in favour of a numeric level. Addresses BUKKIT-818
[Bleeding] Add ability for the Potion class to represent no-effect
potions. Addresses BUKKIT-817

- Potion's type can be null
- Add Potion.setType()
- New Potion constructors which do not take a PotionType parameter
- Potion constructor chainers splash() and extend() added
- Add PotionType.getMaxLevel() and PotionType.isInstant()
- Add PotionType.WATER which is a very special case
- Make PotionType.getDamageValue() public
[Bleeding] Add missing methods to Bukkit class, fix non-static methods, and add a junit test to ensure both these problems will be caught in future.
[Bleeding] Fixed potion tests.
[Bleeding] Add constructor to BlockFromToEvent for dragon egg teleportation. Addresses BUKKIT-828
Added service register and unregister events. Addresses BUKKIT-816
Add a CreateReason to PortalCreateEvent. Addresses BUKKIT-833
Adjust plugin enable/disable logging
Added missing BlockState functions. Addresses BUKKIT-807
Reduced excessive exception handling in NumberConversions. Addresses BUKKIT-825

This also allows, for instance, to parse complex numbers with imaginary part=0, if the according toString method omits zero components.
This also saves some unboxing (Foo.valueOf returns a wrapper, while Foo.parseFoo returns a primitive)
Event system optimizations. Addresses BUKKIT-813

- Made the handlers field a simple array instead of an array of arrays.
- Got rid of the "baked" field.
Narrowed down the return type of most EntityEvent subclasses for convenience. Addresses BUKKIT-809
[Bleeding] Fixed MapPalette.imageToBytes to properly handle transparency. Addresses BUKKIT-852
[Bleeding] Fixes deadlock issue and generic usage. Fixes BUKKIT-844 and fixes BUKKIT-854
[Bleeding] Fixed file handle leak in /timings command. Addresses BUKKIT-853
[Bleeding] Cleaned up unsafe casts. Addresses BUKKIT-844

Removed internal collection leaks from PluginDescriptionFile
BREAKING: PluginDescriptionFile.getAuthors() now returns List instead of
ArrayList

Various places with unsafe generics, notably List<Object> getList() in
Configurations are now referenced as <?>. This is nonbreaking, but
sourcecode will need to be revised when compiled.
[Bleeding] Added a Metadata framework for Entities, Blocks, and Worlds

This metadata implementation has the following features:

- All metadata is lazy. Metadata values are not actually computed until another plugin requests them. Memory and CPU are conserved by not computing and storing unnecessary metadata values.

- All metadata is cached. Once a metadata value is computed its value is cached in the metadata store to prevent further unnecessary computation. An invalidation mechanism is provided to flush the cache and force recompilation of metadata values.

- All metadata is stored in basic data types. Convenience methods in the MetadataValue class allow for the conversion of metadata data types when possible. Restricting metadata to basic data types prevents the accidental linking of large object graphs into metadata. Metadata is persistent across the lifetime of the application and adding large object graphs would damage garbage collector performance.

- Metadata access is thread safe. Care has been taken to protect the internal data structures and access them in a thread safe manner.

- Metadata is exposed for all objects that descend from Entity, Block, and World. All Entity and World metadata is stored at the Server  level and all Block metadata is stored at the World level.

- Metadata is NOT keyed on references to original objects - instead metadata is keyed off of unique fields within those objects. Doing this allows metadata to exist for blocks that are in chunks not currently in memory. Additionally, Player objects are keyed off of player name so that Player metadata remains consistent between logins.

- Metadata convenience methods have been added to all Entities, Players, Blocks, BlockStates, and World allowing direct access to an individual instance's metadata.

- Players and OfflinePlayers share a single metadata store, allowing player metadata to be manipulated regardless of the player's current online status.
Moved getVehicle, leaveVehicle and isInsideVehicle from LivingEntity to Entity. Addresses BUKKIT-811
Fixed null pointer exception in config.getMapList().
Added NETHER_PORTAL and END_PORTAL to the TeleportCause enum. Addresses BUKKIT-265

Added new NETHER_PORTAL and END_PORTAL values to the TeleportCause enum
and relevant constructor for PlayerPortalEvent.