Fixes #327

Looks like something went wrong when implementing 3D mode, and the resulting coordinates list to draw onto images was being clipped to the first two elements.

GetObjectsCoords should only ever return 2D coordinates for objects as they're being mapped onto images. It appears that an attempt was made to have it return 3D, but this was only applied to the query portion rather than the downstream data processing. The attempt to round the third coordinate also doesn't appear to work as intended, though this isn't necessary anyway.

To resolve this I've stripped that part of the function out. If 3D mode does need to show position in 3D then feel free to restore, though I can't see anything trying this in the code.