JCLOUDS-602 - Add support for volumeType, iops and encrypted to EC2 volumes

Note - still missing adding these to the createVolume* methods, but
that's going to involve a non-trivial change to something like
CreateVolumeOptions.class rather than the current simple arguments.
sounds good as long as base cases don't emit (sincethis code is in api/ec2 not provider/aws-ec2). ex. if switching iops to primitive, make sure the base case of zero doesn't emit a query, since that's probably in a later api version, and might puke a clone.