ENH: Maurer for Danielsson in Surface Distance.

In the surface distance filters replace the Danielsson distance map
filter with the Maurer distance map filter, to reduce computation
time.

In the previous patch, two tests were failing that have now been fixed
in this patch. The failure was *not* due to a difference in the
Danielsson and Maurer distance map calculations: these filters appear
to output the same distance maps. There were two reasons why the
tests were failing.

itkSignedMaurerDistanceMapImageFilterTest3 was failing because
SetUseImageSpacing was turned on in the patch whereas it was turned
off previously. This test operates on an image that has image spacing
of 0.26 in both dimensions. Since turning the image spacing on is the
"correct" thing to do, this patch includes a new baseline resulting
from image spacing turned on. The previous patch did not affect the
other two Maurer tests because they operated on images that had a
spacing of 1.

itkHausdorffDistanceImageFilterTest was failing because of a change in
itkDirectedHausdorffDistanceImageFilter.hxx. That filter changed from
using *unsigned* Danielsson to *signed* Maurer distance transforms.
The error resulted from the average Hausdorff distance calculation,
which previously averaged 0 values when regions were overlapping
(because it was using an unsigned distance) but was changed to average
negative values (because it was using a signed distance). This has
been corrected by setting negative distance values to 0 in the
averaging computation. The documentation has been updated to describe
this averaging computation.

This patch addresses the JIRA ticket:
https://itk.icts.uiowa.edu/jira/browse/ITK-3011

Change-Id: I26e0881b32a654a6dcb617ebe9cfa5d3a6905ad6
Merge topic 'PerfSamplePicking'

cb8f280 ENH: Maurer for Danielsson in Surface Distance.