AU: Class to perform delta updates.

A class to perform delta updates and the associated unittests. Also,
change the delta diff generator executable to be able to apply a
delta, which is handy for debugging.

TEST=Attached unit test, hand-tested on real build images
BUG=552

Review URL: http://codereview.chromium.org/1718001
diff --git a/bzip_extent_writer.h b/bzip_extent_writer.h
index fdd9671..acffbac 100644
--- a/bzip_extent_writer.h
+++ b/bzip_extent_writer.h
@@ -23,7 +23,7 @@
   }
   ~BzipExtentWriter() {}
 
-  bool Init(int fd, const std::vector<Extent>& extents, uint32 block_size);
+  bool Init(int fd, const std::vector<Extent>& extents, uint32_t block_size);
   bool Write(const void* bytes, size_t count);
   bool EndImpl();