{    
    "require": {
        "guzzlehttp/guzzle": "~6.0"
    },
    "autoload": {
        "psr-4": { 
            "SublimeArts\\SublimeChimp\\" : "/" 
        }
    }
}

{    
    "require": {
        "guzzlehttp/guzzle": "~6.0"
    },
    "autoload": {
        "psr-4": { 
            "SublimeArts\\SublimeChimp\\Classes\\MailChimp\\" : "classes/MailChimp/" 
        }
    }
}

Revert to the psr-4 setup that worked previously. This is anyways a Travis only issue.
Revert to the psr-4 setup that worked previously. This is anyways a Travis only issue.
