A better module for handling rolling upgrades

This rolls the ec2 elb management script into a module.
Now if an ELB is added or removed "changed" will return True/False
so you can tell if any action was taken based on the coloring of
the response (yellow/green).
the previous module ec2_elb_facts is made obsolete by ec2_elb
updating the rolling upgrade example to use the new module
naming fixes
Merge pull request #41 from edx/jarv/better-elb-rolling

Jarv/better elb rolling