voxelspacing input wasa not handled correctly
initial voxels are now included in to create pdbs
added name and year
During reading of volumefile density, the datatype is changed to np.float64
proportional_orientations now returns also the number of rotations and degree
Added normalize fucntion
voxelspacing was not handled correctly
Removed bugs. Its working again
Rewritten. It now uses the proportional orientation sets