CDAP-735: Update visualization of Spark job metrics

@nistala You mean something like this:

        load: function () {
            var model = this.get('model');
            var self = this;
            var runStatusUpdate = function () {
                self.__updateStatus(model.app, model.name);
            };
            this.__updateStatusInterval = setInterval(runStatusUpdate, this.__STATUS_UPDATE_TIMEOUT);
            this.__updateMetricsInterval = setInterval(this.__updateMetrics, this.__METRICS_UPDATE_TIMEOUT);
        },

        unload: function () {
            clearInterval(this.__updateStatusInterval);
            clearInterval(this.__updateMetricsInterval);
        },

Am I Right?