Oct. 18, 1995  :  Changed input and output of labels as tags to perform
                  one-tag-at-a-time io, avoiding allocation of large amounts
                  of memory.

Dec.  7, 1995  :  Added one function to load labels or tags.
Apr. 16, 1996  :  Made 'cc -fullwarn -lint' proof
Apr. 23, 1996  :  Fixed the bug of double incrementing n_steps_no_improvement
Apr. 29, 1996  :  Added icosahedron to list of building blocks for triangulation
Jul. 31, 1996  :  Changed format of .obj file to have sizes instead of end indic
Aug.  1, 1996  :  Fixed separate_object_points to handle per-vertex colours.
Aug.  6, 1996  :  Sped up ray-tube intersection test
Aug. 20, 1996  :  get_object_normals returns null pointer. 
Nov.  7, 1996  :  Added is_transform_right_handed() to transforms.c
Nov. 25, 1996  :  Added User defined colour coding.
Jun.  6, 1997  :  Fixed label loading to be faster and more correct.
Jun. 13, 1997  :  Fixed plane-polygon intersection program to handle
                  in plane cases better.
Jun. 30, 1997  :  Fixed the bounding problem in scan lines to volume
Jul. 23, 1997  :  Made quadmeshes scanable to volume.
