Other existing, non-unit tests covered 78 percent. This Unit test
alone covers over 90 percent. The remaing uncovered code is for
unusual use cases that are difficult to replicate.

Changes also made to vtkDataSetSurfaceFilter:

COMP: Removed unreachable code. Mainly unreachable Delete's.

COMP: Added missing vtkWarningMacro's

COMP: Added Get() methods to PrintSelf,

COMP: Fixed some spelling errors.