diff --git a/scrapy/crawler.py b/scrapy/crawler.py
index 4ae1c49d8..3866ba76d 100644
--- a/scrapy/crawler.py
+++ b/scrapy/crawler.py
@@ -1,5 +1,4 @@
 import signal
-from itertools import chain
 
 from twisted.internet import reactor, defer
 
diff --git a/scrapy/exceptions.py b/scrapy/exceptions.py
index c22ba0204..4bcecd994 100644
--- a/scrapy/exceptions.py
+++ b/scrapy/exceptions.py
@@ -24,6 +24,7 @@ class CloseSpider(Exception):
     """Raise this from callbacks to request the spider to be closed"""
 
     def __init__(self, reason='cancelled'):
+        super(CloseSpider, self).__init__()
         self.reason = reason
 
 # Items
diff --git a/scrapy/utils/datatypes.py b/scrapy/utils/datatypes.py
index 1c1b54f41..d7fd27143 100644
--- a/scrapy/utils/datatypes.py
+++ b/scrapy/utils/datatypes.py
@@ -6,8 +6,6 @@ This module must not depend on any module outside the Standard Library.
 """
 
 import copy
-from collections import deque, defaultdict
-from itertools import chain
 
 from scrapy.utils.py27 import OrderedDict
 
@@ -46,7 +44,7 @@ class MultiValueDict(dict):
         try:
             list_ = dict.__getitem__(self, key)
         except KeyError:
-            raise MultiValueDictKeyError, "Key %r not found in %r" % (key, self)
+            raise MultiValueDictKeyError("Key %r not found in %r" % (key, self))
         try:
             return list_[-1]
         except IndexError:
@@ -124,7 +122,7 @@ class MultiValueDict(dict):
     def update(self, *args, **kwargs):
         "update() extends rather than replaces existing key lists. Also accepts keyword args."
         if len(args) > 1:
-            raise TypeError, "update expected at most 1 arguments, got %d" % len(args)
+            raise TypeError("update expected at most 1 arguments, got %d" % len(args))
         if args:
             other_dict = args[0]
             if isinstance(other_dict, MultiValueDict):
@@ -135,7 +133,7 @@ class MultiValueDict(dict):
                     for key, value in other_dict.items():
                         self.setlistdefault(key, []).append(value)
                 except TypeError:
-                    raise ValueError, "MultiValueDict.update() takes either a MultiValueDict or dictionary"
+                    raise ValueError("MultiValueDict.update() takes either a MultiValueDict or dictionary")
         for key, value in kwargs.iteritems():
             self.setlistdefault(key, []).append(value)
 
diff --git a/scrapy/utils/url.py b/scrapy/utils/url.py
index 4ef014fd9..918042064 100644
--- a/scrapy/utils/url.py
+++ b/scrapy/utils/url.py
@@ -5,10 +5,12 @@ library.
 Some of the functions that used to be imported from this module have been moved
 to the w3lib.url module. Always import those from there instead.
 """
+import posixpath
 import urlparse
 import urllib
 import cgi
 
+# scrapy.utils.url was moved to w3lib.url and import * ensures this move doesn't break old code
 from w3lib.url import *
 from scrapy.utils.python import unicode_to_str