Emit some kind of error for missing or additional fields in write

[rom1504]

Additional fields are currently ignored (see https://github.com/PrismarineJS/node-minecraft-protocol/blob/master/src/protocol.js#L1503)
Missing fields are currenlty passed as undefined.

It would be better to emit some error.
Related to PrismarineJS/mineflayer#269

[rom1504]

same as #127

[roblabla]

Missing is easy to do. Additional might have some non-acceptable overhead though.

[rom1504]

Missing is mostly about throwing an error if value[typeArg.name] is undefined there https://github.com/roblabla/ProtoDef/blob/master/src/datatypes/structures.js#L134

I'm not sure if checking for additional fields has any use. And yeah, it would mean going through the value object keys, which can be a little costly.

[rom1504]

moved tracking to ProtoDef-io/node-protodef#61