pregame: added AllowAttackPreGame

When set to 'false', attacks made during preGame animate on the client
and are not processed by the server or other clients. I'd love to see
this matured into something that doesn't even animate the client.
Use Hook
Merge pull request #1 from BrightPaul/patch-5

Use Hook
pregame: use SetupClassHook
Merge pull request #233 from lancehilliard/develop

pregame: added AllowAttackPreGame