Clean up package loading in preamble

Basically, just list them in alphabetical order.
Change chapter and sectioning

This commit removes the "parts" and replaces them with chapters;
it also bumps every   section type down to reflect the change.
The sections now do not reset at new parts.

As part of this change, I've removed the "AUTHORS.tex" file and
just put myself as the author.
Tweak URL formatting

Replace "<address>" with "<<address>>" (but prettier) and remove
some trailing "/"es.