Add Support for multiple YAML commands as an array

[gogglespisano]

I would like to send multiple commands to be executed sequentially. The code appears to support a command list when the JSON is send as multiple lines.

It would be nice is it would also accept a JSON list of commands so they could be entered in YAML.

      input:
        - command: play_message
          number: "{{ internal_id }}"
          ...
        - command: play_audio_file
          number: "{{ internal_id }}"
          ...
        - command: hangup
          number: "{{ internal_id }}"
          ...