Added a side panel mechanism and a simple Panel as an example. Check the keyboard function to see how the menu is initialized. I could not find a fix for using mulitple viewports and accurately raycasting the mouse while the menu was open and as such mouse function in the world are disabled until the menu is open. The menu can still be interacted with however with the mouse. Also added various visual enhancements. The View area is now scaled with the size of the window instead of being stretched. You can also change to a fullscreen mode by hitting + (Shift =). I also reduced the size of the map to a 5x5 cube. We can shrink it more but 5x5 could be a good overshot goal.
Solved Git merge conflicts. The entities update function will now be called through the loop. If you need to use it, now u can.
Fixed a bug where objects would be drawn over by adjacent cells when not quite at the next cell.