STYLE: Improve SoftwareGuide documentation

There were errors in the processing of the ITKSoftwareGuide
example generation.

Only provide base image name for LaTeX
By only providing the base image name for LaTeX includegraphics,
then pdflatex or other tools can choose an image that is
most appropriate for that document building style.
For example pdflatex prefers .png images, adn latex prefers
.eps files.

Remove unused SoftwareGuide key word.
The NORMALIZE_EPS_OUTPUT_OF key word was not being processed
by the SoftwareGuide parsing.

The software guide formatting and reference code
for more consistent coding standards.

Change-Id: I09b64f43aad28ed309ea0c695ee5ebf08adfbc4b
Merge topic 'ITKSoftwareGuideUpdates_combined'

e3aff16 STYLE: Improve SoftwareGuide documentation