Menu: View->Reference axes
Allows the user to draw a reference frame for the model, being able to:
- display the x, y, z axis, and change their colours
- display a reference grid for each of the xy, yz, xz planes
- define the number of subdivisions for the grid reference
- change the colours of all these.
The configuration options of the reference axes are: 
an example of this option can be seen in this image:
