Anti-Heli Rush code
AI Harvester rebuilding code
Fix for Repair thresholds (again)

Fix for cheese walling, covers Units and Infantry in:
Guard, Area Guard, Hunt. Also Units/Infantry that are part of Teams on Offensive missions.
Also some fixes to pathfinding, so Units with adequate weaponry can set paths through enemy Walls.

The AI's Walls and any Walls on-map at game start will not be attacked.

Also updates to building repair percentages.

Now announces mod version, an additional check for Refinery blockers. Some checks on Turret placement to stop traffic jams and Harvesters will now try to move to a different Refinery if their 'homeplate' is in use.

Revamped Skirmish AI

Engineer fixes