code: function updateTooltip(dataPoint, xPosition, yPosition) {
              updateContent(dataPoint);
              updatePositionAndSize(dataPoint, xPosition, yPosition);
          }
docs: Updates tooltip title, content, size and position
  sorts by alphatical name order if not forced order given
  
  @param  {lineChartPointByDate} dataPoint  Current datapoint to show info about
  @param  {Number} xPosition           Position of the mouse on the X axis
  @return void
  @private