+0.5.2-b4 - 5/4/2000
+ Renamed pictures to phantoms, objects to phantom elements
+ Continued code cleanup
+
+0.5.2-b3 - 4/30/200
+ More code cleanup with reorganizing libraries
+ Added --log and --exp to sdf-1
+ Allowed negative numbers for window levels in CGI interface
+
+0.5.2-b2 - 4/30/200
+ Continued code cleanup
+
0.5.2-b1 - 4/29/2000
Fixed a few MPI bugs
Better documented, coded raysum in-memory on on-disk options