+ move docs into a different folder

+ added more docs on serialization

docs/src/docbkx/reference/introduction.xml

@@ -0,0 +1,22 @@
+<partintro>
+   <title>Document structure</title>
+
+   <para>This part of the reference documentation explains the core functionality
+   offered by Spring GemFire integration.</para>
+
+   <para><xref linkend="bootstrap"/> describes the configuration support provided for
+   bootstrapping, initializing and accessing a GemFire cache or region.</para>
+   
+   <para><xref linkend="serialization"/> describes the enhancements for GemFire 
+   (de)serialization process and management of associated objects.
+   </para>
+
+   <para><xref linkend="apis"/> explains the integration between GemFire API and
+   the various "data" features available in Spring, such as transaction management
+   and exception translation.
+   </para>
+
+   <para><xref linkend="testing"/> showcases various ways of testing GemFire inside
+   Spring framework.</para>
+
+</partintro>