Feature/sdk 15

[JeremyCraigMartinez]

New feature to add automatic retries to any API calls that end with the following errno's:

var RETRIABLE_ERRORS = [
    'ECONNRESET',
    'ENOTFOUND',
    'ESOCKETTIMEDOUT',
    'ETIMEDOUT',
    'ECONNREFUSED',
    'EHOSTUNREACH',
    'EPIPE',
    'EAI_AGAIN'
];

Issue originated from #12

[dzdidi]

AFAIK: agent is the same through all the code base. So it can be just hardcoded and there will be no need to pass it as a parameter.
stringify, contentLength dont look like really necessary as a parameter as well.

Logic for authorization can be moved inside the function (like it was before).

[JeremyCraigMartinez]

• agent is a local variable to the object Session/Connect. It cannot be hard coded in this generalized function
• Connection's query_api's content type is application/x-www-form-urlencoded which requires a different type of stringifying querystring.stringify, you can read more about this here. Session's query_api's content type is application/json which requires the stringying function JSON.stringify.
• contentLength, see new commit