Implement a check for overlaps

[lobis]

It would be really useful to have a native way to check for overlaps when building the geometry. At the moment I do this using root (https://root.cern/doc/master/classTGeoManager.html#afa2bfedf7f02398fdf5867072a77a884).

[altavir]

We discussed it about a year ago with @Zelenyy and it is really hard to do and probably impossible on the level of gdml library because it requires a fully-fledged geometry engine. It is probably possible to implement using an external tool or on the rendering stage.

[altavir]

Actually, it could be done with https://commons.apache.org/proper/commons-geometry/index.html. I do not have time for that right now, but if there is a student willing to practice, it should take no longer, than few weeks (or a few days for experienced guy).

[lobis]

I don't think there is anyone else in our end with enough interest to do this. I may look into it when I have time, looks like I could learn quite a bit from this.