Relay errors

[Opisek]

Kick minecraft clients with error messages if an error occurs.

[Opisek]

Without an error message (generic disconnect), this should be as easy as sending

0x030000

See: https://minecraft.wiki/w/Minecraft_Wiki:Projects/wiki.vg_merge/Protocol#Disconnect_(login)

Might be interesting to have configurable levels of verbosity, including no disconnect messages at all (just closing the socket).