Major Combat AI Improvements

Siege Combat AI complete rewritten
AI will properly use siege towers and ladders
Fixed issues with AI towers not attaching and going in circles
Tower and ladders will now detach after attaching to move to attack never level of defenses
AI is highly proficient in sieges now with most towns can be sieged in minutes
Greatly increased the difficulty when AI attacks walled player towns
AI will now attack and destroy player buildings during field combat and sieges
Fixed various exploits with getting too much resources during sieges due to AI being inactive or slow
Fixed issues when taking large number of units up walls
Stability improvements during large sieges
Fixed some instances of crashing when changing between levels
Various balancing improvements with combat AI
Started work on rebalancing world map AI
Fixed issue when construction palisade walls in towns