Update virtualbox to work with new btrfs images.
Update amazon-instance to work with new btrfs images.
Fail on any error during script execution.
Fix up Amazon instance-store privisioning.
Support additional storage on Amazon instance-store.
Do not inline provisioning scripts.
Add coreos-image-tools.
Keep all provisioning files in ./files and run a single script for
provisioning.
Use EC2 us-east-1 Ubuntu mirror as it seems to be sane for Trusty.
Move builder specific files into their own directories.