Minor tweaks to tutorial

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@792646 13f79535-47bb-0310-9956-ffa450edef68

src/docbkx/advanced.xml

@@ -21,7 +21,7 @@
     under the License.
     ====================================================================
 -->
-<chapter>
+<chapter id="advanced">
     <title>Advanced topics</title>
     <section>
         <title>Custom client connections</title>

src/docbkx/authentication.xml

@@ -21,7 +21,7 @@
     under the License.
     ====================================================================
 -->
-<chapter>
+<chapter id="authentication">
     <title>HTTP authentication</title>
     <para>HttpClient provides full support for authentication schemes defined by the HTTP standard
         specification. HttpClient's authentication framework can also be extended to support

src/docbkx/connmgmt.xml

@@ -21,7 +21,7 @@
     under the License.
     ====================================================================
 -->
-<chapter>
+<chapter id="connmgmt">
     <title>Connection management</title>
     <para>HttpClient has a complete control over the process of connection initialization and
         termination as well as I/O operations on active connections. However various aspects of

src/docbkx/httpagent.xml

@@ -21,7 +21,7 @@
     under the License.
     ====================================================================
 -->
-<chapter>
+<chapter id="httpagent">
     <title>HTTP client service</title>
     <section>
         <title>HttpClient facade</title>

src/docbkx/statemgmt.xml

@@ -21,7 +21,7 @@
     under the License.
     ====================================================================
 -->
-<chapter>
+<chapter id="statemgmt">
     <title>HTTP state management</title>
     <para>Originally HTTP was designed as a stateless, request / response oriented protocol that
         made no special provisions for stateful sessions spanning across several logically related