Apply transform to content bounding volume

[javagl]

Fixes #321

When there was a tile with a transform, and content that had a boundingVolume, then the transform was only applied to the tile bounding volume, but not to the content bounding volume. This was a leftover from the original/"legacy" bounding volume checks, and caused a BOUNDING_VOLUMES_INCONSISTENT to be reported erroneously.

Fortunately, it was an easy fix.

I did add a test for the case of bounding box objects. But in general, some parts of the "legacy" bounding volume containment checks could receive some additional coverage. It would be nice to cover the whole cartesian product of

• box and box
• box and sphere
• box and region
• sphere and box
• sphere and sphere
• sphere and region
• region and box
• region and sphere
• region and region

both with and without transform, and a positive and a negative case, respectively. But I'd have to allocate more time to actually create these 36 tilesets...