P0-B2: Part 1086: Improvements, Debugging

I have been continuing on with the debugging and testing for the eproject.

I have made some further improvements to the AI system, and I have also improved the grass exclusion system, although there are more updates needed here later.

I have also added the ability to save and load the game while the player is driving a (ground) vehicle. Previously only ships and flying vehicles worked with the save system.