Fixed the "starting" URL referenced in README - /whoami does not
exist any more, so following the instructions gave a "Not Found"
error.

Re-ordered the README sections to put things needed most often or
by more users up front; moved things most people will not need to
know towards the end.  (Very little content is new/changed; most
is just rearranged.)

Updated create_key.sh to be more test-friendly, and document how
to deploy newly generated keys; added a pointer to it in README.

Also added notes about the presence of alternate configs - and
warned novice users away from them for now.

Since the README already says to point a browser at localhost, it
was surprising to see the listeners bound to 0.0.0.0 by default.
Changed that and added notes in README about how to change it if
the user really wants to make a test listener accessible
externally.

Updated output messages during startup to include the bound IP,
to make this more obvious.

Added a missing EOL or two.

Usually just a word or punctuation; occasionally I rewrote a sentence
if I had a hard time determining what was meant by the original. (N.B.
if I misunderstood something, then my re-wording will be wrong!)

Also added eol to many files that were missing it, which throws off
'cat somefile' at a shell prompt (but did not yet touch anything under
src/, which also has many files without eol).

I did not re-line-wrap the text I changed, so that the diffs are
minimized and meaningful changes are easier to spot.