* don't mix " and '
* rename functions that perform changes
* add diff, reorganize _present/_absent functions
* update tests to match function reorg
* add result to _exit_hostvars and removal of possibly sensitive information
* shallow copy dict for proper diff, add check_mode
* set check_mode to False for unit tests
* move _parse_meta back to it's original place
* use get_openstack_vars for diff when not in check_mode
* add changelog fragment
