Workaround for floating point errors

[SevenSpheres]

Generating a large number of stars, in a small radius, at a large distance, can cause multiple stars to be in the same place due to floating point errors. Example:

The workaround would be to determine the scale of the error from the distance (1 ly per 2^24 ly), make a list of all the xyz coordinates, and for each star check the distance from every coordinate and make sure it's more than the error.