Added a method to AVMService and its dependent services to get an InputStream

directly from a node descriptor.  It's a minor optimization for a few use
scenarios.  It's also convenient for accessing content of historical file
versions directly.  
Another CLT, to list the versions of a store.


git-svn-id: https://svn.alfresco.com/repos/alfresco-enterprise/alfresco/HEAD/root@4496 c4b6b30b-aa2e-2d43-bbcb-ca4b014f7261

source/java/org/alfresco/repo/avm/LayeredFileNodeImpl.java

@@ -247,6 +247,7 @@ class LayeredFileNodeImpl extends FileNodeImpl implements LayeredFileNode
         throw new AVMException("Should not be called.");
     }
     
+    // TODO The lPath argument is unnecessary.
     /**
      * Get the ContentData for this file.
      * @return The ContentData object for this file.