* Add reusable convex regions * Add test * Test local bounding boxes * Add functions to adjust interior/exterior bounding boxes * Add interior bbox for cone * Rename ConvexRegion to ConvexRegionInterface * Reformat test * Reduce unit test printing output to work better with single precision * Add convex surface bzone joiner * Prevent negative zeros in simplified cone origin * Remove unneessary explicit keyword * REVERTME: move second-order convex regions to a follow-on PR * Improve docs * Add to-do note