[AWS|ELB] add ProxyProtocolPolicyType (and formatting)
[AWS|ELB] add set_load_balancer_policies_for_backend_server request
[AWS|ELB] add support for seeing backend server descriptions
[AWS|ELB] add support for OtherPolicies
Merge pull request #2008 from mikehale/elb-updates

[AWS|ELB] proxy protocol support