aws_inventory

adding ability to use env var AWS_PROFILE

adding ability to specify what ec2 metadata variable populates the ansible_host attribute.

making failure to find ec2_metadata variable more graceful

adding conditional to local nodename inclusion in inventory to prevent overwriting a possible previous inclusion

adding more hostvar matching options. splitting out hostvars assignment into private method. adding hostvars capability for localhost. removing hardwired ansible_connection hostvar from localhost.