DOC: Fix Software Guide page overruns in IterativeClosestPoint{1,2}.cxx.

Split up the literal code section.

Change-Id: I921913032ce143c413ba734c77af8ad5dd6cc4d0
DOC: Remove duplicate text in LaplacianRecursiveGaussian example.

This appears to be a copy/paste error from the
SmoothingRecursiveGaussianImageFilter.

Change-Id: I81dd7ccd6b563495a7521bce722036169d994aa1
Merge topic 'icp-sections'

805669f4 DOC: Remove duplicate text in LaplacianRecursiveGaussian example.
fd398023 DOC: Fix Software Guide page overruns in IterativeClosestPoint{1,2}.cxx.