Add BlockDeviceMapping to CreateImage and RunInstances

This change add BlockDeviceMapping to CreateImage and RunInstances. While
testing against AWS the error "The parameter BlockDeviceMapping is not
recognized" was occurring until the Version was changed to a more recent
API version.
Merge pull request #2 from markpeek/markpeek-blockdevicemapping

Add BlockDeviceMapping to CreateImage and RunInstances
ec2: ability to specify IOPS on block device mapping