lib/google-contacts.js
function (clientId, clientSecret) {
    this._clientId=clientId
    this._clientSecret=clientSecret
    this._auth = new googleAuth.OAuth2(clientId, clientSecret, '');
}
function (clientId, clientSecret) {
    this._clientId=clientId
    this._clientSecret=clientSecret
    this._auth = new googleAuth.OAuth2(clientId, clientSecret, '');
}
@classdesc
This class interact with Google Contacts API.

@param {String} clientId     The client id
@param {String} clientSecret The client secret key
@constructor