USC: fixed parameters / added descriptor-type

Fixed the descriptor parameters matching the values of the original
paper (Tombari et al. 2010). The former values have been copied from
3DSC-descriptor and have not been adapted.

Added a descriptor type UniqueShapeContext1960.

Modified test case to match the new UniqueShapeDescriptor.
Merge pull request #856 from jgarstka/USCfix

USC: fixed parameters / added descriptor-type