Document non-mac running

[clburlison]

The entire process needs more documentation. The readme also needs love.

The required keys

        prefs = {
            'bucket': os.environ.get('bucket_name'),
            'region': os.environ.get('AWS_REGION'),
         }

The following extra prefs need better documentation when using the non-mac platform option.

            'ExtraArgs': {
                'ACL': 'public-read',
                'StorageClass': 'REDUCED_REDUNDANCY',
                'Metadata': {
                    'Cache-Control': '86400',
                },
            },
            'default_class': 'REDUCED_REDUNDANCY',
            'default_age': '86400',
            'catalogs_age': '120',
            'manifests_age': '120',