Revert viewport size

lib/tools/phantomas/phantomasWrapper.js

@@ -29,7 +29,6 @@ var PhantomasWrapper = function() {
             'js-deep-analysis': task.options.jsDeepAnalysis || false,
             'user-agent': 'Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/27.0.1453.110 Safari/537.36',
             'screenshot': task.options.screenshot || false,
-            'viewport': '1366x768',
 
             // Mandatory
             'reporter': 'json:pretty',