Doxygen - another sample, preliminary comments

[Benjamin Kosnik]

> More ideally, if you can do RELEASE-NOTES, I can take those bits from
> there and put them into the FAQ as appropriate; status.html should
> also be updated to reflect current reality.  But I don't view those as
> life-and-death issues or anything.

I can do this today. Where do I check in the revised file, though? 
libstdc++-v3/docs/17_intro or some other location?

-benjamin