Major progress on Gradle port

Complete:
--------
- src/* documentation resources moved to 'docs' subproject

- docbook sources upgraded to Docbook 5

- formatted all docbook sources to strip tab characters and
  eliminate trailing whitespace

- all projects compile and test successfully

- all artifacts upload successfully to s3, static.sf.org, etc.

Remaining:
---------
- documentation L&F needs work. CSS, images, and highlighting aren't
  hooked up properly

- spring-integration-jdbc codegen bits in Maven POM need to be
  transcribed into gradle

- dependencies that were optional or provided scope in maven are
  currently 'compile' scope in Gradle.  Need to figure out support
  in Gradle to fix this.

- run through Eclipse classpath and project generation scenarios

- delete all Maven artifacts

docs/src/reference/docbook/security.xml

@@ -0,0 +1,64 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<chapter xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="security"
+    xmlns:xlink="http://www.w3.org/1999/xlink">
+  <title>Security in Spring Integration</title>
+
+  <section id="security-intro">
+    <title>Introduction</title>
+    <para>
+      Spring Integration provides integration with the
+      <ulink url="http://static.springframework.org/spring-security/site/">Spring Security project</ulink>
+      to allow role based security checks to be applied to channel send and receive invocations.
+    </para>
+  </section>
+
+  <section id="securing-channels">
+    <title>Securing channels</title>
+       <para>
+      Spring Integration provides the interceptor <classname>ChannelSecurityInterceptor</classname>, which extends
+      <classname>AbstractSecurityInterceptor</classname> and intercepts send and receive calls on the channel.  Access decisions
+      are then made with reference to <classname>ChannelInvocationDefinitionSource</classname> which provides the definition of
+      the send and receive security constraints.  The interceptor requires that a valid <interfacename>SecurityContext</interfacename>
+      has been established by authenticating with Spring Security, see the Spring Security reference documentation for details.
+  </para>
+  <para>
+    Namespace support is provided to allow easy configuration of security constraints.  This consists of the secured channels tag which allows
+    definition of one or more channel name patterns in conjunction with a definition of the security configuration for send and receive.  The pattern
+    is a <interfacename>java.util.regexp.Pattern</interfacename>.
+    <programlisting language="xml"><![CDATA[<?xml version="1.0" encoding="UTF-8"?>
+<beans:beans xmlns="http://www.springframework.org/schema/integration"
+   xmlns:si-security="http://www.springframework.org/schema/integration/security"
+  xmlns:beans="http://www.springframework.org/schema/beans"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xmlns:security="http://www.springframework.org/schema/security"
+  xsi:schemaLocation="http://www.springframework.org/schema/beans
+      http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
+      http://www.springframework.org/schema/security
+      http://www.springframework.org/schema/security/spring-security-2.0.xsd
+      http://www.springframework.org/schema/integration
+      http://www.springframework.org/schema/integration/spring-integration-2.0.xsd
+      http://www.springframework.org/schema/integration/security
+      http://www.springframework.org/schema/integration/security/spring-integration-security-2.0.xsd">
+
+<si-security:secured-channels>
+    <si-security:access-policy pattern="admin.*" send-access="ROLE_ADMIN"/>
+    <si-security:access-policy pattern="user.*" receive-access="ROLE_USER"/>
+</si-security:secured-channels>]]>
+  </programlisting>
+
+  By default the secured-channels namespace element expects a bean named <emphasis>authenticationManager</emphasis> which implements
+  <interfacename>AuthenticationManager</interfacename> and a bean named <emphasis>accessDecisionManager</emphasis> which implements
+  <interfacename>AccessDecisionManager</interfacename>.  Where this is not the case references to the appropriate beans can be configured
+  as attributes of the <emphasis>secured-channels</emphasis> element as below.
+  <programlisting language="xml"><![CDATA[<si-security:secured-channels access-decision-manager="customAccessDecisionManager"
+                              authentication-manager="customAuthenticationManager">
+    <si-security:access-policy pattern="admin.*" send-access="ROLE_ADMIN"/>
+    <si-security:access-policy pattern="user.*" receive-access="ROLE_USER"/>
+</si-security:secured-channels>]]>
+  </programlisting>
+
+    </para>
+  </section>
+
+
+</chapter>