Upgrade vulcanize to 0.7.6.

node_modules/vulcanize/lib/vulcan.js

Index: node_modules/vulcanize/lib/vulcan.js
diff --git a/node_modules/vulcanize/lib/vulcan.js b/node_modules/vulcanize/lib/vulcan.js
index 0d7e230add04c5c206444bfe6264e4081cdbedcf..82c3969256dd67a74beef5bb660dfeaff6610995 100644
--- a/node_modules/vulcanize/lib/vulcan.js
+++ b/node_modules/vulcanize/lib/vulcan.js
@@ -10,7 +10,6 @@
 
 // jshint node: true
 
-var cssom = require('cssom');
 var fs = require('fs');
 var path = require('path');
 var uglify = require('uglify-js');
@@ -200,19 +199,13 @@ function compressJS(content, inline) {
 }
 
 function compressCSS(content) {
-  var out;
-  try {
-    var ast = cssom.parse(content);
-    out = ast.toString();
-  } catch (e) {
-    if (options.verbose) {
-      console.log('Error parsing CSS:', e.toString());
-      console.log('Falling back to removing newlines only');
-    }
-    out = content;
-  } finally {
-    return out.replace(/[\r\n]/g, '');
-  }
+  // remove newlines
+  var out = content.replace(/[\r\n]/g, '');
+  // remove css comments (/* ... */)
+  out = out.replace(/\/\*(.+?)\*\//g, '');
+  // remove duplicate whitespace
+  out = out.replace(/\s{2,}/g, ' ');
+  return out;
 }
 
 function removeCommentsAndWhitespace($) {