Added item deletion; changed item management

All TF2 Game Coordinator related things are in the namespace
SteamBot.TF2GC
Changes `AutoStartBots` setting to `AutoStartAllBots`

Fixes #293
Made SetGamePlaying public
Merge pull request #294 from FunkyLoveCow/setting_name_change

Changes `AutoStartBots` setting to `AutoStartAllBots`