changes TOC settings to make all components reachable, again

[SVN r36814]

doc/Jamfile

@@ -12,6 +12,6 @@ boostbook quickbook
         <xsl:param>chunk.first.sections=1
         <xsl:param>toc.section.depth=3
         <xsl:param>toc.max.depth=3
-        <xsl:param>generate.section.toc.level=1
+        <xsl:param>generate.section.toc.level=4
     ;