NavMesh For Pathfind quick fix

The built-in nav mesh was much easier to use than expected.

Initial release

In this release, you can control the red army while the green one will be static.

Controls:
LMB to select unit.
RBM to set a destination/attack an enemy unit.
RBM + LShift to set a path for the selected unit.
Space to highlight the paths of all the controlled units.
R to reload the scene.
Esc to exit the game.