/teammsg is not logged, allowing for it to be abused

In a public server environment, /teammsg allows for silent unlogged chat which is open to abuse.

For example: a Vanilla SMP server puts players into a scoreboard team in the spawn area to disable PvP. A problem arises that a rogue player could spam everyone in the spawn area with team messages, and the server administration wouldn't be able to react on time, for every incident

A resolution would be to add a /team option for toggling the team messages, preferably disabled by default