Adds 1.7.10 protocol version 5 support, a major update with significant changes.
Expands https://github.com/iceiix/steven/issues/18 Enhance protocol support
* Add v1_7_10 protocol packet structures and IDs
* EncryptionRequest/Response i16 variant in login protocol
* 1.7.10 slot NBT data parsing
* Support both 1.7/1.8+ item::Stack in read_from, using if protocol_verson
* 1.7.10 chunk format support, ChunkDataBulk_17 and ChunkData_17
* Extract dirty_chunks_by_bitmask from load_chunks17/18/19
* Implement keepalive i32 handler
* Send PlayerPositionLook_HeadY
* Send PlayerBlockPlacement_u8_Item_u8y
* Handle JoinGame_i8_NoDebug
* Handle SpawnPlayer_i32_HeldItem_String
* BlockChange_u8, MultiBlockChange_i16, UpdateBlockEntity_Data, EntityMove_i8_i32_NoGround, EntityLook_i32_NoGround, EntityLookAndMove_i8_i32_NoGround
* UpdateSign_u16, PlayerInfo_String, EntityDestroy_u8, EntityTeleport_i32_i32_NoGround
* Send feet_y = head_y - 1.62, fixes Illegal stance
https://wiki.vg/index.php?title=Protocol&oldid=6003#Player_Position
> Updates the players XYZ position on the server. If HeadY - FeetY is less than 0.1 or greater than 1.65, the stance is illegal and the client will be kicked with the message “Illegal Stance”.
> Absolute feet position, normally HeadY - 1.62. Used to modify the players bounding box when going up stairs, crouching, etc…
* Set on_ground = true in entity teleport, fixes bouncing
* Implement block change, fix metadata/id packing, bounce _u8 through on_block_change
* Implement on_multi_block_change_u16, used with explosions
Cleans up https://github.com/iceiix/steven/pull/57 1.8.9 (47) multiprotocol support
which added too much code duplication, Metadata19 vs Metadata18, and
different packets for each, the only difference being how it was parsed.
Instead, switch back to using only one Metadata implementation, but with
parsing conditionalized on a new global mutable: SUPPORTED_PROTOCOL_VERSION.
Accessing global mutable state is unsafe but it is only set when
initializing the connection, and only read when deep enough in the code
where it is not feasible to pass otherwise. More elegant, worth it.
iceiix