Reduce LabelGeometry instantiation by restricting intensity to real

The combination of images instantiated was too many for the
LabelGeometry image filter. This was causing many system to run out of
memory during compilation of this filter, and way the largest object
filter, and took the longest to compile.

This filter has been reduced to only take real images for the
intensity input.

Change-Id: I3264f7f73c96852cb994c895284a657b270b06ee
STYLE: Ran json through python format script

Change-Id: Ic335f34c70ea9e04999c10f0abf7ccddf493a9ac
Merge topic 'SIMPLEITK-524_AddLabelGeometryImageFilter' into next

a8a62cb4 STYLE: Ran json through python format script
86218a9f Reduce LabelGeometry instantiation by restricting intensity to real