Consistent log messages
Fix destroying EBS volumes / elastic IPs
Update option types

I.e. "types.uniq type.string" -> "types.str".
Typo
Allow EBS volume resources to be attached by direct reference

Meaning you can now say:

  resources.ebsVolumes.data =
    { size = 1000; ... };

  machine =
    { config, pkgs, resources, ... }:
    { deployment.targetEnv = "ec2"; ...

      fileSystems."/data" =
        { autoFormat = true;
          fsType = "ext4";
          device = "/dev/xvdh";
          ec2.disk = resources.ebsVolumes.data;
        };
    };