mussel,test: reorganize folder. refactor tests.
mussel: improve extract_args() to support --key val style.
mussel,test: add basic unit tests for functions.
mussel,test: replace "exit 1" with "return 1".
mussel,test: replace positional variables with names variables.
mussel,test: replace "-z"  with "-n".
mussel,test: add line number to error message.
mussel,test: add parameter validation.
mussel,test: add unit tests for instance and load_balancer.
mussel,test: add unit tests for image.
mussel,test: add unit tests for backup_object.
mussel,test: add "destroy" test for instance and load_balancer.
mussel,test: add unit tests for host_node.
mussel,test: add unit tests for storage_node.
mussel,test: add unit tests for network.
mussel,test: add unit tests for security_group.
mussel,test: add unit tests for ssh_key_pair.
mussel,test: add unit tests for "undefined".
mussel,test: add unit tests for v11.12.
mussel,test: abs_path -> abs_dirname.