Downloading was broken in certain cases on python 2.

FancyUrlopener.urlretrieve was failing on redirect, but in an insidious way, because of a bug in the python-future module:
https://github.com/PythonCharmers/python-future/issues/425
Replace with the requests module for the time being.

requirements.txt

@@ -1 +1,2 @@
 pbxproj==2.5.1
+requests>=2.13

toolchain.py

@@ -20,14 +20,11 @@ import fnmatch
 import tempfile
 from datetime import datetime
 try:
-    from urllib.request import FancyURLopener, urlcleanup
-except ImportError:
-    from urllib import FancyURLopener, urlcleanup
-try:
+    import requests
     from pbxproj import XcodeProject
     from pbxproj.pbxextensions.ProjectFiles import FileOptions
 except ImportError:
-    print("ERROR: pbxproj requirements is missing")
+    print("ERROR: Python requirements are missing")
     print("To install: pip install -r requirements.txt")
     sys.exit(0)
 curdir = dirname(__file__)
@@ -65,15 +62,6 @@ def cache_execution(f):
         state[key_time] = str(datetime.utcnow())
     return _cache_execution
 
-
-class ChromeDownloader(FancyURLopener):
-    version = (
-        'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 '
-        '(KHTML, like Gecko) Chrome/28.0.1500.71 Safari/537.36')
-
-urlretrieve = ChromeDownloader().retrieve
-
-
 class JsonStore(object):
     """Replacement of shelve using json, needed for support python 2 and 3.
     """
@@ -468,11 +456,16 @@ class Recipe(object):
         if exists(filename):
             unlink(filename)
 
-        # Clean up temporary files just in case before downloading.
-        urlcleanup()
-
         print('Downloading {0}'.format(url))
-        urlretrieve(url, filename, report_hook)
+        headers = {'User-agent': 'Mozilla/5.0 (X11; Linux x86_64) '
+                   'AppleWebKit/537.36 (KHTML, like Gecko) '
+                   'Chrome/28.0.1500.71 Safari/537.36'}
+
+        r = requests.get(url, headers=headers)
+
+        with open(filename, "wb") as fw:
+            fw.write(r.content)
+
         return filename
 
     def extract_file(self, filename, cwd):