Always use cPickle, never 'regular' pickle.

This fixes #18.

rq/job.py

@@ -1,6 +1,6 @@
 import times
 from uuid import uuid4
-from .pickle import loads, dumps, UnpicklingError
+from cPickle import loads, dumps, UnpicklingError
 from .proxy import conn
 from .exceptions import UnpickleError, NoSuchJobError
 

rq/pickle.py

@@ -1,9 +0,0 @@
-from __future__ import absolute_import
-try:
-    import cPickle as pickle
-except ImportError:
-    import pickle  # noqa
-
-loads = pickle.loads
-dumps = pickle.dumps
-UnpicklingError = pickle.UnpicklingError

rq/worker.py

@@ -8,7 +8,7 @@ import procname
 import socket
 import signal
 import traceback
-from .pickle import dumps
+from cPickle import dumps
 try:
     from logbook import Logger
     Logger = Logger    # Does nothing except it shuts up pyflakes annoying error

tests/test_job.py

@@ -2,7 +2,7 @@ import times
 from datetime import datetime
 from tests import RQTestCase
 from tests.helpers import strip_milliseconds
-from rq.pickle import loads
+from cPickle import loads
 from rq.job import Job
 from rq.exceptions import NoSuchJobError, UnpickleError