added a method to visit sub-directory

src/main/java/org/kohsuke/github/GHContent.java

@@ -1,6 +1,8 @@
 package org.kohsuke.github;
 
 import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
 
 import javax.xml.bind.DatatypeConverter;
 
@@ -107,6 +109,25 @@ public class GHContent {
         return "dir".equals(type);
     }
 
+    /**
+     * List immediate children of this directory.
+     */
+    public PagedIterable<GHContent> listDirectoryContent() throws IOException {
+        if (!isDirectory())
+            throw new IllegalStateException(path+" is not a directory");
+
+        return new PagedIterable<GHContent>() {
+            public PagedIterator<GHContent> iterator() {
+                return new PagedIterator<GHContent>(owner.root.retrieve().asIterator(url, GHContent[].class)) {
+                    @Override
+                    protected void wrapUp(GHContent[] page) {
+                        GHContent.wrap(page,owner);
+                    }
+                };
+            }
+        };
+    }
+
     public GHContentUpdateResponse update(String newContent, String commitMessage) throws IOException {
         return update(newContent, commitMessage, null);
     }