Base Defense

[rmacgill]

• Army units in/near base should respond to attacks.

• Probes in base should defend against very early rushes that we're not prepared to defend against. Note that we have a rush detection mechanism that's based on game-time so, if it's triggered, we could send probes. If we're under attack and it's not triggered, it's a mid to late-game attack and probes will be useless.

• Ramp blocking, photon cannons, etc. where appropriate.