Fixed cython compile errors

Author: Oliver Smith

transfers.py

@@ -1,7 +1,11 @@
+from __future__ import absolute_import, with_statement, print_function, division, unicode_literals
+
+from tradeexcept import TradeException
 from urllib.parse import urlencode
 from urllib.request import Request, urlopen
-import urllib.error
+
 import time
+import urllib.error
 
 
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