Readding the old disconnect messages in IRC.

[Anna Bakker]

In IRC when someone ingame disconnected, it would say: "Player left the game (disconnect.Quitting)" or .<reason>

This was helpful to see if someone crashed, or if they just left the game.

[Riot]

reorganising disconnect messages and separating from not-allowed-to-connect messages, resolves #277

→ <<cset d2f738d4aeb4>>

[Riot]

Updating disconnected and disallowed messages, resolves #151, #277

→ <<cset 5e31f1251c7e>>