Revert "Remove appendix A (manpages)"

This reverts commit 27651fead9eb04bfceb0ee646186ad5cead2e7c2.

Let's do it another way that still preserves the references in
the text.
redo manpage removal, this time preserving in-text references

also, add a pointer to http://man.netbsd.org/
dissertation -> book, at least mostly
update claims about which NetBSD sources we describe