move ulib and urlparse to compat

pydu/compat.py

@@ -4,10 +4,14 @@ import sys
 
 PY2 = sys.version_info[0] == 2
 
-# urljoin
+# urllib, urlparse and urljoin
 if PY2:
+    import urllib as ulib
+    import urlparse
     from urlparse import urljoin
 else:
+    import urllib.request as ulib
+    import urllib.parse as urlparse
     from urllib.parse import urljoin
 
 # Dictionary iteration

pydu/request.py

@@ -1,16 +1,9 @@
 import os
 import shutil
 import tempfile
-from pydu.compat import PY2, string_types
+from pydu.compat import string_types, ulib, urlparse
 from pydu.string import safeunicode
 
-if PY2:
-    import urllib as ulib
-    import urlparse
-else:
-    import urllib.request as ulib
-    import urllib.parse as urlparse
-
 
 class FileName(object):
     @staticmethod