echo.lua is abusable with ChanServ's FANTASY commands

The old TuxBot (the Python one) had this issue too, until we fixed it: TuxBot needs to prefix the output of every command with the nick of the user who triggered the command. Or, at least, echo.lua needs to do this, because echo.lua can be abused like this:

!echo !kick ToBeFree
!kick ToBeFree
-*- ToBeFree has been kicked by ChanServ

This can be abused even more by spamming "!echo !help", which makes TuxBot answer with a lot of "!help" lines, which work exactly like "/msg ChanServ help" and thus spam services until TuxBot and anyone on the same IP is automatically banned from the whole network for spamming services.

I fixed this in my TuxBot by disabling echo.lua and by disabling FANTASY commands in #linux, but that's just a workaround. :)