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.cc b/bzip_extent_writer.cc
index cdf0ce3..e200e2d 100644
--- a/bzip_extent_writer.cc
+++ b/bzip_extent_writer.cc
@@ -14,7 +14,7 @@
 
 bool BzipExtentWriter::Init(int fd,
                             const vector<Extent>& extents,
-                            uint32 block_size) {
+                            uint32_t block_size) {
   // Init bzip2 stream
   int rc = BZ2_bzDecompressInit(&stream_,
                                 0,  // verbosity. (0 == silent)