Section 7.1 historical note

From Yadis

The note about the considered plain text format can be omitted, or at least moved out of the main flow of the text to a footnote or endnote.

I feel we should leave this in for now. It can be removed in due course.

For now, it is important that we include our discussion of the alternatives, in response to the objections that have been raised to using an XML document. I feel this note is in the right place for that. There are no footnotes nor endnotes in the spec.

Let's remove the note when we have the Overview and the Implementer's Guide. Folks are starting to work on those, so it should not be long.

--Joaquin