createDataTable Function needs to be rebuilt to support multiple columns about chartkick

[StephenOTT]

current createDataTable JS function:

    var createDataTable = function(series, columnType) {
      var data = new google.visualization.DataTable();
      data.addColumn(columnType, "");

      var i, j, s, d, key, rows = [];
      for (i = 0; i < series.length; i++) {
        s = series[i];
        data.addColumn("number", s.name);

        for (j = 0; j < s.data.length; j++) {
          d = s.data[j];
          key = (columnType === "datetime") ? d[0].getTime() : d[0];
          if (!rows[key]) {
            rows[key] = new Array(series.length);
          }
          rows[key][i] = toFloat(d[1]);
        }
      }

      var rows2 = [];
      for (i in rows) {
        if (rows.hasOwnProperty(i)) {
          rows2.push([(columnType === "datetime") ? new Date(toFloat(i)) : i].concat(rows[i]));
        }
      }
      if (columnType === "datetime") {
        rows2.sort(sortByTime);
      }
      data.addRows(rows2);

      return data;
    };

[StephenOTT]

@ankane Looking more at the code, I am thinking the renderPieChart may be a good example to deal with multiple columns of data with little or no code changes to CreateDataTable?

[StephenOTT]

@ankane in the renderPieChart function:

 renderPieChart = function(element, series, opts) {
      waitForLoaded(function() {
        var chartOptions = {
          chartArea: {
            top: "10%",
            height: "80%"
          }
        };
        var options = merge(merge(defaultOptions, chartOptions), opts.library || {});

        var data = new google.visualization.DataTable();
        data.addColumn("string", "");
        data.addColumn("number", "Value");
        data.addRows(series);

        var chart = new google.visualization.PieChart(element);
        resize( function() {
          chart.draw(data, options);
        });
      });
    };

Can you explain why the options variable is different compared to the other render functions?
PieChart:

var options = merge(merge(defaultOptions, chartOptions), opts.library || {});

Linechart and other render functions:

var options = jsOptions(series, opts);

Same goes with the BarChart. The options are showing as:

        var chartOptions = {
          hAxis: {
            gridlines: {
              color: "#ccc"
            }
          }
        };

[StephenOTT]

Okay have the basic code working for timelines. Will continue code work on issue #39