title: google chart api draws negative axis as well though minValue is 0
body: <p>I have a google chart as follows which plots Age for various IDs. However, as age cannot be negative, I want it to be only on the positive axis. </p>
  
  <p>I have given the minValue for vertical axis as 0, however it still shows the negative axis. How can I fix this?</p>
  
  <p>My code below</p>
  
  <pre><code>function AgeChart() {
      google.load("visualization", "1", {packages:["corechart"]});
  
      var age_data = new google.visualization.DataTable();
      var divname = "agediv";
  
      age_data.addColumn('number', 'ID');
      age_data.addColumn('number', 'Age');
  
  
      age_data.addRow([1,10]);
      age_data.addRow([1,20]);
      age_data.addRow([1,30]);
      age_data.addRow([1,40]);
      age_data.addRow([1,50]);
  
  
      var options = {'title':'Age line graph',
          curveType: 'function',
          viewWindowMode:'explicit',
          vAxis: {title: 'Age (years)',
              minValue: 0,
          },
          hAxis: {title: 'ID'},
          height: 600,
          width: 1000
      };
  
      var chart = new google.visualization.LineChart(document.getElementById(divname));
      chart.draw(age_data, options);
  }
  </code></pre>
  
  <p>EDIT: After adding the viewWindow.min value, it works for me.</p>
  
  <pre><code>   function AgeChart() {
          google.load("visualization", "1", {packages:["corechart"]});
  
          var age_data = new google.visualization.DataTable();
          var divname = "agediv";
  
          age_data.addColumn('number', 'ID');
          age_data.addColumn('number', 'Age');
  
  
          age_data.addRow([1,10]);
          age_data.addRow([1,20]);
          age_data.addRow([1,30]);
          age_data.addRow([1,40]);
          age_data.addRow([1,50]);
  
  
          var options = {'title':'Age line graph',
              curveType: 'function',
              viewWindowMode:'explicit',
             vAxis: {title: 'Age (years)',
              minValue: 0,
              viewWindowMode:'explicit',
              viewWindowMode:'explicit',
              viewWindow:{
                  min:0,
                }
              },
          hAxis: {title: 'ID'},
              height: 600,
              width: 1000
          };
  
          var chart = new google.visualization.LineChart(document.getElementById(divname));
          chart.draw(age_data, options);
      }
  </code></pre>