title: Highlighting edges with Cytoscape JS doesn't work
body: <p>I want to highlight outgoing edges after clicking on node. Now, I have such code:</p>
  
  <pre><code>style: cytoscape.stylesheet()
    .selector('node')
      .css({
        'content': 'data(id)',
        'background-color': '#4286f4'
      })
    .selector('edge.highlighted')
      .css({
        'line-color': 'black',
        'target-arrow-color': '#b830f7'
      })
    .selector('edge')
      .css({
        'curve-style': 'bezier',
        'target-arrow-shape': 'triangle',
        'width': 4,
        'line-color': '#4286f4',
        'target-arrow-color': '#4286f4'
      }),
   //else parameters
   });
  cy.on('click', function(e){
      var edges = cy.edges();
      edges.removeClass('highlighted');
  });
  cy.on('click', 'node', function(e){
      var id = e.target.id();
      var outgoing = cy.edges("[source='" + id + "']")
      outgoing.addClass('highlighted');
  });
  </code></pre>
  
  <p>And when line-color isn't set by 'edge' selector it works fine, but if I set some color to edges - new color doesn't apply after clicking on node. </p>