ansible vars list groups output tweak
	renamed:    ansible-vars -> ansible-inventory
introduce --tree option
	new file:   ansible-inventory-dump
ansible-inventory tweaks, limit on depth, ..
re-enable host parsing
ansible-inventory-dump:

rewrite after ansible inventory refactor was merged
prepare to merge this script with ansible-inventory
import human_log.py callback

https://gist.github.com/cliffano/9868180
http://blog.cliffano.com/2014/04/06/human-readable-ansible-playbook-log-output-using-callback-plugin/"
merge ansible-inventory and ansible-imventory-dump