[DAS2] HTML document re-org complete

[Steve Chervitz]

I just committed my large, re-organizational changes to das2_get.html, so
others can now feel free to edit at will.

Summary of what I did:

* Re-organized into three main sections for consistency, readability:
    - General
    - Overview
    - Detailed
* Simplified top summary table and fixed in-page navigation links.
* Added TOC and subsection TOCs.
* Added section numbers.
* Added global sequence id section.
* Misc typo fixes and wording improvements.
* Noted a bad sentence in the third paragraph. Not sure the intent
  here ("some fetching some of the documents"?)

The biodas.org viewable version of this document does not yet have these
changes as I write: http://biodas.org/documents/das2/das2_get.html . It
operates off of the anonymous CVS server which hasn't yet sync'd with the
dev CVS server. Not sure how often this sync happens.

I updated the biodas.org site to sync with CVS hourly, so the docs viewable
from there will stay more current, but still may be out of date during this
time of frequent updates.

Steve