Prof examples

[nicholascar]

Updates to SVG to remove colour and add white backgrounds.

This PR was initially branched from other unrelated branches (for property definitions & alignments, subjects of PRs #827 & #828 respectively) so I've removed those PRs changes by reverting 3 commits.

This PR should now only contain edits to examples - the section in the HTML doc and files within examples/ - and a small chift of non-example figures to a new figures/ folder for neatness of source files.

[rob-metalinkage]

Editorial and formatting improvements and non-normative examples.

[nicholascar]

See this preview of the changed document: https://raw.githack.com/w3c/dxwg/prof-examples/profilesont/index.html#examples

[aisaac]

I am ok with doing these changes. I must say though that I may still have some comments on existing examples and diagrams, and I am not sure that this PR fixes any of the outstanding issues.
But at this point I am convinced that we need to see the new version to facilitate further discussion and feedback and move forward.

I also have one doubts: one of the commits seem to add at least one significant example, the CSIRO one:
912a211
(actually I think in total three examples are added)
Again I'm not against showing it for discussion, but I didn't have the time to check it.

And I am quite sure that this makes this PR a non-editorial one, so I'm going to remove the 'editorial' label to it

[nicholascar]

Thanks Antoine. The example you mention that was added - the CSIRO one - was already there but as a loose example in the examples/ folder, not added into the document.