Implement Grid System to track grid data

[WestonVincze]

Maintain a data structure to represent the necessary data of a grid cell and its contents in order to easily identify entities within the cell

• determine if item(s) exist
• check the number of units
• movement altering data (slow, etc)

Create helper functions to convert floating point positions into grid coordinates and implement a system that automatically updates the grid data

We could even add listeners or triggers on specific grid cells to invoke specific actions