Preparing the v0.4 release

Update version strings
Update the Changelog and README
Update copyright year in various files

Change-Id: If746211e0b36e59d4f3de977b81df082f2da9fe3
diff --git a/errors.py b/errors.py
index a812883..aec4619 100644
--- a/errors.py
+++ b/errors.py
@@ -1,5 +1,6 @@
-#  Copyright 2014 Linaro Limited
-#  Author: Dave Pigott <dave.pigot@linaro.org>
+#  Copyright 2014-2015 Linaro Limited
+#  Authors: Dave Pigott <dave.pigot@linaro.org>,
+#           Steve McIntyre <steve.mcintyre@linaro.org>
 #
 #  This program is free software; you can redistribute it and/or modify
 #  it under the terms of the GNU General Public License as published by