* cloudformation: dummy check mode
* cloudformation: use changesets to implement check mode
* cloudformation: wait at most 5min for change set
* cloudformation: handle stack creation and deletion in check mode
* cloudformation: standardize output format in check mode
msg is a string, meta is a list
* cloudformation: use same naming convention in get_changeset as create_changeset
also add comment about code duplication between said functions
* Remove unused imports
* PEP8 whitespace fix
* Fix CI, convert success=True check to for/else