Merge pull request #131 from simoncozens/docs

Use gtk-doc to build user's manual as well as reference

diff --cc docs/usermanual-ch03.xml
index 4f289ce,fd63e74..3a26c55
--- 1/docs/usermanual-ch03.xml
--- 2/docs/usermanual-ch03.xml
+++ b/docs/usermanual-ch03.xml
@@@ -56,10 -56,10 +56,10 @@@ void somefunc(hb_buffer_t *buffer) 
        Now we have a brand new Harfbuzz buffer. Let's start filling it
        with text! From Harfbuzz's perspective, a buffer is just a stream
        of Unicode codepoints, but your input string is probably in one of
 -      the standard Unicode character encodings (UTF-8, UTF-16, UTF-3 )
 +      the standard Unicode character encodings (UTF-8, UTF-16, UTF-32)
      </para>
-   </sect2>
-   <sect2 id="setting-buffer-properties">
+   </section>
+   <section id="setting-buffer-properties">
      <title>Setting buffer properties</title>
      <para>
      </para>