Fix RegionUtils.initSDKRegions

RegionUtils.initSDKRegions tries to load the /etc/regions.xml file in the classpath using a leading /, which does not work with ClassLoader.getResourceAsStream. 

The proposed fix uses the sorter solution RegionUtils.class.getResourceAsStream("/etc/regions.xml"), but would also work if the leading slash was removed : classLoader.getResourceAsStream("etc/regions.xml").
Add missing SNS actions.
Version 1.5.4 of the AWS Java SDK

This release adds support for Amazon Simple Notification Service's new mobile push API, introduces a utility for testing Amazon EC2 operation permissions, and resolves several issues reported by customers.
Merge pull request #106 from dipthegeezer/further_actions

Add missing SNS actions
Merge pull request #71 from clementdenis-vv/patch-1

Fix RegionUtils.initSDKRegions