New design code

[bsautron]

• When a error occurs, it send once in the callback.
• All errors is an ApiError class which have the status code of response, and array of errors
• Easy to add a new Api path like this:

// add to the `api` attribute
'getProfile': {method: 'GET/json', path: '/user/v4/profile', auth: true}

// and call the methode:
api.getProfile(callback)
// If data required:
api.sendSamples(data, callback)

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