Usage example
var Durango = require('durango'),
payment = Durango({
user: 'demo',
pass: 'password'
});
payment.sale({
amount: 0.99,
card: '4111111111111111',
expire: '1025',
cvv: '',
owner: 'JOHN SMITH'
}, function( err, data ){
console.log(err, data);
});