P0-A8: Part 833: AI, Navigation

I have been working on adding the complex nav meshes to the dynamic structures, so that the AI characters can automatically transition to and from interiors.

This was quite difficult to get working properly, but it now works. I have also made changes to the AI action code so that the AI can perform a variety of actions in any location or within any interior.

I have also fixed a number of bugs and issues with the AI and navigation code. I am quite pleased with how this system is working.