Introduced 4.0 versions of all XML configuration schemas

Removed spring-beans.dtd (the 1.x variant) and spring-oxm-1.5.xsd (pre-Spring-Framework variant), in order to raise the backwards compatibility limit a little bit at least. We'll keep supporting the 2.0 and 2.5 xsd versions for the time being, as well as spring-beans-2.0.dtd.

Removed the ref 'local' attribute in spring-beans-4.0.xsd since 'local' lost its differentiating role to a regular bean ref back in the 3.1 days when we started allowing for the same bean id to reappear in a different beans section of the same configuration file (with a different profile).

Issue: SPR-10437

src/reference/docbook/beans-dependencies.xml

@@ -627,7 +627,7 @@ public class ExampleBean {
 
         <programlisting language="xml">&lt;property name="targetName"&gt;
  <lineannotation>&lt;!-- a bean with id 'theTargetBean' must exist; otherwise an exception will be thrown --&gt;</lineannotation>
- &lt;idref local="theTargetBean"/&gt;
+ &lt;idref bean="theTargetBean"/&gt;
 &lt;/property&gt;</programlisting>
 
         <para>A common place (at least in versions earlier than Spring 2.0)
@@ -677,7 +677,7 @@ public class ExampleBean {
         errors as early as possible) if the target bean is in the same XML
         file.</para>
 
-      <programlisting language="xml">&lt;ref local="someBean"/&gt;</programlisting>
+      <programlisting language="xml">&lt;ref bean="someBean"/&gt;</programlisting>
 
       <para>Specifying the target bean through the <literal>parent</literal>
         attribute creates a reference to a bean that is in a parent container of