Add "twisted" entry to uses.xml, remove Zope entry from main book.

Modified version of patch supplied.

Submitted by:	Marcus von Appen <mva@FreeBSD.org> in -doc

en_US.ISO8859-1/books/porters-handbook/book.xml

@@ -7887,21 +7887,6 @@ _DOCSDIR=	.
 		distribution).</entry>
 	    </row>
 
-	    <row>
-	      <entry><varname>USE_TWISTED</varname></entry>
-	      <entry>Add dependency on twistedCore.  The list of
-		required components can be specified as a value of
-		this variable.  Example:
-		<literal>web lore pair flow</literal></entry>
-	    </row>
-
-	    <row>
-	      <entry><varname>USE_ZOPE</varname></entry>
-	      <entry>Add dependency on Zope, a web application
-		platform.  Change Python dependency to Python 2.7.
-		Set <varname>ZOPEBASEDIR</varname> containing a
-		directory with Zope installation.</entry>
-	    </row>
 	  </tbody>
 	</tgroup>
       </table>

en_US.ISO8859-1/books/porters-handbook/uses.xml

@@ -386,6 +386,35 @@
     <varname>lua_CMD</varname>.</entry>
 </row>
 
+<row>
+  <entry><literal>twisted</literal></entry>
+  <entry>(none), <literal>ARGS</literal></entry>
+
+  <entry>Add a dependency on <application>twistedCore</application>.
+    The list of required components can be specified as a value of
+    this variable. <literal>ARGS</literal> can be one of:
+
+    <itemizedlist>
+      <listitem>
+	<para><literal>build</literal>: add
+	  <application>twistedCore</application> or any specified
+	  component as build dependency.</para>
+      </listitem>
+
+      <listitem>
+	<para><literal>run</literal>: add
+	  <application>twistedCore</application> or any specified
+	  component as run dependency.</para>
+      </listitem>
+    </itemizedlist>
+
+    Besides <literal>build</literal> and <literal>run</literal>, one
+    or more other supported <application>twisted</application>
+    components can be specified.  Supported values are listed in
+    <filename>Uses/twisted.mk</filename>.
+  </entry>
+</row>
+
 <row>
   <entry><literal>uidfix</literal></entry>
   <entry>(none)</entry>