fixes #67 - open not working in ubuntu

lib/util/open.js

@@ -1,15 +1 @@
-var sh = require('shelljs')
-  , debug = require('debug')('open');
-
-module.exports = function(url) {
-  var command = 'open';
-
-  url = url || '';
-
-  if (process.platform === 'win32') {
-    command = 'start'; 
-  }
-  command += ' ' + url;
-  debug(command);
-  sh.exec(command, {async: true});
-};
+module.exports = require('opener');

package.json

@@ -34,7 +34,8 @@
     "doh": ">=0.0.4",
     "step": ">=0.0.5",
     "forever-monitor": "1.1.x",
-    "keypress": "~0.1.0"
+    "keypress": "~0.1.0",
+    "opener": "~1.3.0"
   },
   "devDependencies": {
     "mocha": "*",