Improved pathing, doors and using the environment

Hey survivors!

Some of the biggest pieces of feedback we received from content creators taking a look at our pre-alpha demo was:

1. Poor pathing and movement animations
2. Lack of doors for structures
3. Inability to use the whole vertical environment for building and strategic positioning

Behold! Characters now:

* Run smoothly
* Path intelligently
* Use doors and
* Can get up cliffsides

Till next time. Keep surviving ... (by not getting stuck on the in-game environment)