Add Python util to read from a data pipe into a bytearray

The implementation of this function is inspired by
//mojo/common/data_pipe_utils.cc. It will be used in an upcoming CL.

R=qsr@chromium.org

Review URL: https://codereview.chromium.org/952223002
diff --git a/mojo/python/mojo_utils/__init__.py b/mojo/python/mojo_utils/__init__.py
new file mode 100644
index 0000000..50b23df
--- /dev/null
+++ b/mojo/python/mojo_utils/__init__.py
@@ -0,0 +1,3 @@
+# Copyright 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.