Updates to handle EC2-VPC changes

Some updates to deal with some of the complications added with the
switch to default-vpcs.
Merge pull request #74 from andylyall/2013.07

Updates to handle EC2-VPC changes
[maven-release-plugin] prepare release dasein-cloud-aws-2013.07.4
[maven-release-plugin] prepare for next development iteration
Merge branch '2013.07'
Updating version