Add a function to construct AWS parameters from configuration data; BlockDeviceMapping accepts all allowed configuration keywords -- This makes it possible to change the size of the root device.
Avoid hardcode the index of the BlockDeviceMappings. If the target device is aleady in the list, modify its configuration directly. Otherwise, add a new BlockDeviceMapping with a proper index.
Add doc about changing the size of the root device in AWS
Bump AWS API version to 2013-10-01 and added support for the NetworkInterface keyword. This keyword helps automatically allocated a public ip address for a instance launched in a subnet.