(WIP) ansible-4188 - Making the ec2_elb module more useful for more people

The main use case I need is the ability to replace the contents of
an ELB with another set of instances.  Along the way, this requires
the module to be able to operate on multiple instances as well as
multiple ELBs at a time.

A bunch of refactoring was done while attempting to preserve all
existing functionality. If I did break something, that was not
intended and needs to be fixed.

This is a WIP, so I left all of the debugging code in there for now.
Once people are satisified, I will remove and create a pull request
to ansible.