Very early look at elevation, pathfinding and movement

While this video captured a quick demo using an older codebase, it demonstrates some key features necessary for isometric grid based combat quite nicely. These are elevation, pathfinding and movement. You can see from the video that the units can only move a certain distance according to their movement score, and can also only reach a certain height according to their jump score. Different movement types are also implemented which basically boil down to `walk`, `hop` and `jump` (I don't think we'd implemented a jump animation I was happy with yet when this was recorded though). 

Pathfinding is also shown here, so the units know how to get to where they are going and avoid any obstacles that are in their way. We're using Pathfinding.js for this, and it's pretty amazing, definitely check it out if you have any need for a great JavaScript based path finding library. I'm sure the code could be refactored for other languages as well.