Account for \0 and optimize a little

This was done in 6bbf82342740d5d6841f62a5304dfd8883f5abc3,
but undone (incorrectly) in 645c7e218b9ac87ca287a051a19f4afa3298fcd5
Add ECHO command for debugging purposes
Wrap USERHOST reply, if it's too long
Add NICK :)