Visualize a grid floor

[NihanthCW]

Visualize default Grid floor:
3D orientation arrows are invaluable and currently the only means to orient the user in 3D space. While these might not be as critical with data overlaid on a map, with datasets that don’t map to a specific geographic location (Eg. CM-1 simulation of a cloud, tornado) navigating the space can be disorienting. Suggestion: Include a grid floor at either z=0 or the lowest z value- similar to other modeling software. This could also serve as a default surface for the 3D cursor if one is implemented.

[sgpearse]

Related to #3462