Add  arch to Instance
ec2: RegisterImage
aws: make GetMetaData public
aws: timeout on requesting metadata
ec2: CreateVolume
ec2: DeleteVolume
ec2: AttachVolume
ec2: Volumes
ec2: DetachVolume
Added IAM Instance Profile support
Merge pull request #5 from jmassara/iam_role

Added IAM Instance Profile support
ec2: support more registerimage options