I went through all the Asciidoc files to correct spelling, grammar,
punctuation, and usage. Wherever possible, I also made it more clear and more concise.
I also added links wherever they were reasonable.
Accommodating changes that came while I was editing
Various folks made changes (one of which I recommended) to the documents
while I spent a month editing.
I had to edit that new and changed content as well, so I need this second commit.
Accommodating Artem's requested changes for `aggregator.adoc`
Artem reviewed `aggregator.adoc` as a starting point, so that
he could get some questions answered.
I have made the changes he requested (and answered his questions on Github).
f3bf2a68d6
