3D object consistency

This is a major security release containing the fix for the issue 71, which is mandatory for everyone.

1. 3D object shape consistency check on new block import:
2. Vertex {} points to an invalid halfedge
3. Halfedge {} pointed to by vertex {} does not start in that vertex, but instead in {}
4. Vertex {} does not point to a halfedge
5. Halfedge {} points to an invalid twin halfedge {}
6. Halfedge twin pointed to by halfedge {} does not point back to halfedge
7. Invalid orientation: The halfedge {} and its twin halfedge {} points to the same vertex {}
8. Halfedge {} does not point to a twin halfedge
9. Halfedge {} points to an invalid vertex {}
10. Halfedge {} does not point to a vertex
11. Halfedge {} points to an invalid face {}
12. Halfedge {} points to a face but not a next halfedge
13. Halfedge {} points to an invalid next halfedge {}
14. Halfedge {} points to a next halfedge but not a face
15. Halfedge next pointed to by halfedge {} does not point back to halfedge
16. Length of edge {} is too small
17. Face {} points to an invalid halfedge {}
18. Halfedge pointed to by face {} does not point to back to face
19. Face {} does not point to a halfedge
20. Area of face {} is too small ({})
21. Vertex {} and Vertex {} is connected one way, but not the other way
22. Vertex {} and Vertex {} is connected by multiple edges
23. Volume > 0.1 * bound_volume