* Added PlayerDataSaveEvent, resolved#487
* Added getPlayer() to PlayerDataSaveEvent
may return an IPlayer
* Fixed quit messages
This TranslationContainer vs. string mess... >_<
This condition has been useless since before NBT was introduced to PocketMine.
If there was a use for it, it should have been placed BEFORE anything attempted to read from the NBT.
However, Server now handles bad data automatically now, so Server->getOfflinePlayerData() will never _not_ return a CompoundTag. Hence I've added a CompoundTag type-hint.
Re-implement chunk sending, send chunks inside a radius instead of below a count
This sends chunks in concentric squares around players. When the radius is hit, it will pad out the radius until a full circle of chunks is loaded around the player.
TODO: implement radius-per-tick, send chunks in concentric circles, use radius for player spawning.
To set your server chunk radius, change `view-distance` in server.properties. Values are intended to be the same as MCPE render distance values. With matching client and server render distances the chunks should reach the horizon.
NOTE: You may notice significantly increased memory usage per player when increasing these values to something respectable. This is normal and expected.
A player with render distance 14 for example will cause loading of 600+ chunks. A player cannot however exceed the render distance limit set in server.properties - the server will simply not send any more chunks.
Render distance of 8 chunks is approximately 200 chunks. This is roughly equivalent to the original default max-chunks of 192 in pocketmine.yml, but sent in a circle instead of a square.
Wait for client to request a chunk radius before ordering chunks
Use 8 for default maximum radius (roughly matches old setting of 192)
Calculate spawn chunk count from chunk-sending.spawn-radius
Refactored level\format\generic\GenericChunk -> level\format\Chunk.
Re-added support for async chunk sending
Refactored most Level IO into new namespaces for more organisation
Removed LevelDB loader completely (will be re-added at a later date)
