Update aws.md

Update to 1.8
Added explicitly required maven dependencies (it's a nightmare for a new user to figure this on his own)
Added explicitly correct imports (some are very confusing)

Need to do the same for S3.
This is one possible dependency set, but we definitely don't want to recommend that people use `jclouds-all` all the time. Similarly, you may not want log4j as your logging framework. So I think we need some comments here.