Spring RTS Engine

Lua callin. Would activate when a Unit starts Guarding something. Could then be used to trigger various useful Lua, depending on the behaviors needed.

We just need a generic call whenever a command is executed, in the vein of allow and fallback.

The problem's specific to Guarding. There is code that causes Units to be at a certain distance, and basically they halt at that point, but they aren't Idle, they're just passively Guarding. If had a way to see when that occurs (and if the distance could be played with) then various behaviors become possible. Guard is one of those things that's still very much engine-side atm.