load balancer acceptance specs

This provides acceptances tests for ELB Load Balancer and resolves CLOUD-43,
CLOUD-44, CLOUD-45, CLOUD-46, and CLOUD-48.

This is pretty much the same that @garethr did in GH-18 and supersedes
that work.
(refactor) rename Ec2Helper to AwsHelper
(refactor) use get_* instead of find_*

This matches better with the naming convention established with the plural of
the same in the AwsHelper.