title: Angular Chart.js fill= false not working
body: <p>I have a line chart using angular-chart:  <a href="http://jtblin.github.io/angular-chart.js/" rel="nofollow noreferrer">http://jtblin.github.io/angular-chart.js/</a>
  , and Im trying to remove the fill below the lines.</p>
  
  <pre><code>     &lt;canvas id="line" class="chart chart-line" chart-data="ctrl.data"
              chart-colors="colors"
              chart-labels="ctrl.labels" chart-series="ctrl.series" chart-options="ctrl.options"
              chart-dataset-override="ctrl.datasetOverride" chart-click="onClick"&gt;
      &lt;/canvas&gt;
  </code></pre>
  
  <p>This are my option. Ive tried with fill:false and dataFill:false</p>
  
  <pre><code>  vm.options = {
            type:'line',
            datasetFill:false,
            scales: {
              xAxes: [{
                type:"time",
                time:{
                  min: vm.initialTime,
                  max: vm.endTime
                },
                position: 'bottom'
              }]
            }
          };
  </code></pre>
  
  <p>Ive also tried adding the colors option like this:</p>
  
  <pre><code>$scope.colors = [{
          backgroundColor : '#0062ff',
          pointBackgroundColor: '#0062ff',
          pointHoverBackgroundColor: '#0062ff',
          borderColor: '#0062ff',
          pointBorderColor: '#0062ff',
          pointHoverBorderColor: '#0062ff',
          fill: false /* this option hide background-color */
      }, '#00ADF9', '#FDB45C', '#46BFBD'];
  </code></pre>
  
  <p>and got no results.</p>
  
  <p>Can anyone help me with this problem?</p>