nd-safir.py: fix issue with floating point images in x86_64 arch
nd-safir.py: match default dimensionality options with ndsafir_priism.
nd-safir.py: move text of parent-child relationship to their description field.

Instead of adding a comment to each image refering to other, append the text to
each image description field. This is more standard.
Use the text "ImageID: number" on the description since Omero interprets it as
a link (undocumented feature).
nd-safir.py: time dimensionality must be always true or it will crash
doc: use normal text for documentation instead of javadoc.
nd-safir.py: fix whitespace, variable name and undefined variables for pylint.
nd-safir.py: make sure files get removed when ndsafir_priism fails.

If for some reason a call to ndsafir_priism fails, the temporary input image
and log files were not being removed since cleaning was being done in main()
and run_ndsafir() never returned the filepath for those files.