Multi-protocol Support

[roblabla]

This issue is here to track support of multiple protocols.

[rom1504]

related to PrismarineJS/minecraft-data#9 and PrismarineJS/node-minecraft-protocol#65

[deathcap]

With PrismarineJS/node-minecraft-protocol#331, can enable dynamic cross-version protocol support at least in node-minecraft-protocol with this change (for example):

--- a/examples/echo.js
+++ b/examples/echo.js

 var bot = mineflayer.createBot({
+  version: false,
   host: process.argv[2],
   port: parseInt(process.argv[3]),
   username: process.argv[4] ? process.argv[4] : "echo",

The client will no longer be kicked when connecting to a 1.9 (15w40b) server, as it would from 1.8.9. But the chunk format changed, at least lib/plugins/blocks.js would need to be updated:

mineflayer $ node examples/echo.js localhost 9999
You are using a pure-javascript implementation of RSA.
Your performance might be subpar. Please consider installing URSA

assert.js:89
  throw new assert.AssertionError({
  ^
AssertionError: 61696 === 31613
    at addColumn (/Users/admin/games/voxeljs/mineflayer/lib/plugins/blocks.js:85:12)
    at Client.<anonymous> (/Users/admin/games/voxeljs/mineflayer/lib/plugins/blocks.js:188:5)
    at emitTwo (events.js:87:13)
    at Client.emit (events.js:172:7)
    at Parser.<anonymous> (/Users/admin/games/voxeljs/node-minecraft-protocol/dist/client.js:92:16)
    at emitOne (events.js:77:13)
    at Parser.emit (events.js:169:7)
    at readableAddChunk (/Users/admin/games/voxeljs/node-minecraft-protocol/node_modules/readable-stream/lib/_stream_readable.js:195:16)
    at Parser.Readable.push (/Users/admin/games/voxeljs/node-minecraft-protocol/node_modules/readable-stream/lib/_stream_readable.js:162:10)
    at Parser.Transform.push (/Users/admin/games/voxeljs/node-minecraft-protocol/node_modules/readable-stream/lib/_stream_transform.js:145:32)

[rom1504]

Yeah handling high level features in a cross version way is something to be done before that can works. I described one way I think could work in PrismarineJS/node-minecraft-protocol#231
Basically it's kind of needed to have some kind of abstraction layer on top of packets which would be version independent and that mineflayer could rely on.
It would also be possible to build that within mineflayer to begin with, not sure if that would be simpler than doing it generally though.

[rom1504]

well for the chunk part, the various format should probably just be handled by prismarine-chunk (part of prismarine-world)

[rom1504]

multi-protocol support is there. Dynamic cross version tracked in #468