Another pass.

Markup fixes :

• </programlisting> should end without a newline.
• More <filename> markup.
• Add <structname>, <function>, <replaceable>, <acronym>, <quote> tags.
• Move <programlistings> outside of <para>s.

Grammar fixes :

• Add missing words, where needed.
• Remove superfluous words.
• Shorten several redundant sentences of the form 'Also, .... , as well.'