enable EC2 inventory module to use Name tag as destination

Allows you to use the EC2 tag Name (or any other tag) as a destination address so that the hostname shows up correctly during playbook runs. Requires the names to be resolvable in DNS of course. The implementation allows you to specify a list of instance attributes to try in order, so if the Name tag is not available, you can have it fall back to some other attribute such as the private_ip_address.