If specs fail in node, they should exit with a non-zero exit code

grunt/tasks/spec.js

@@ -1,7 +1,10 @@
 var shell = require('shelljs');
+var grunt = require('grunt');
 
 module.exports = {
   execSpecsInNode: function() {
-    shell.exec("node spec/node_suite.js --color=true")
+    if (shell.exec("node spec/node_suite.js --color=true").code !== 0) {
+      grunt.fail.fatal("Specs Failed");
+    }
   }
-};
+};