Introduce "Aware" superinterface

All existing *Aware interfaces have been refactored to extend this
new marker interface, serving two purposes:

    * Easy access to a type hierarchy that can answer the question
      "What *Aware interfaces are available?", without requiring
      text-based searches. Also clearly excludes false positives like
      TargetClassAware and ParamAware, which while similarly named,
      are not semantically similar to traditional *Aware interfaces
      in Spring.

    * Minor potential performance improvements in
      AbstractAutowireCapableBeanFactory and
      ApplicationContextAwareProcessor. Both have blocks of sequential
      instanceof checks in order to invoke any *Aware interface callback
      methods. For a bean that implements none of these interfaces,
      the whole sequence can be avoided by guarding first with
          if (bean instanceof Aware) {
              ...
          }

Implementors of custom *Aware-style interfaces (and presumably
the BeanPostProcessors that handle them), are encouraged to refactor to
extending this interface for consistency with the framework as well as
the points above.

org.springframework.web/src/main/java/org/springframework/web/context/ServletConfigAware.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2006 the original author or authors.
+ * Copyright 2002-2011 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,6 +18,8 @@ package org.springframework.web.context;
 
 import javax.servlet.ServletConfig;
 
+import org.springframework.beans.factory.Aware;
+
 /**
  * Interface to be implemented by any object that wishes to be notified
  * of the ServletConfig (typically determined by the WebApplicationContext)
@@ -28,10 +30,11 @@ import javax.servlet.ServletConfig;
  * elsewhere, an exception will be thrown on bean creation.
  *
  * @author Juergen Hoeller
+ * @author Chris Beams
  * @since 2.0
  * @see ServletContextAware
  */
-public interface ServletConfigAware {
+public interface ServletConfigAware extends Aware {
 
 	/**
 	 * Set the ServletConfig that this object runs in.

org.springframework.web/src/main/java/org/springframework/web/context/ServletContextAware.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2005 the original author or authors.
+ * Copyright 2002-2011 the original author or authors.
  * 
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,16 +18,19 @@ package org.springframework.web.context;
 
 import javax.servlet.ServletContext;
 
+import org.springframework.beans.factory.Aware;
+
 /**
  * Interface to be implemented by any object that wishes to be notified
  * of the ServletContext (typically determined by the WebApplicationContext)
  * that it runs in.
  *
  * @author Juergen Hoeller
+ * @author Chris Beams
  * @since 12.03.2004
  * @see ServletConfigAware
  */
-public interface ServletContextAware {
+public interface ServletContextAware extends Aware {
 
 	/**
 	 * Set the ServletContext that this object runs in.