- Refactoring rename Class TagManager to TagLayerManager
- Added Layer Property in class Unit.cs
- Updated method InitializeDefaultTagAndLayer in class ZombieSquad
and VampireSquad
- Layers now are instancied at run time if the user ommit to specify a layer
by default the human layer is set to any gameObject that have an Unit.cs script
attached to it's component. Idem for ZombieSquad and VampireSquad
