Pass additional options in Task.retry

Additional options like queue or routing_key were not being correctly passed to apply_async when a task is retried.
Try to fix django settings problem on Windows.  Fixes celery/django-celery/#228
crontab hour has to be str not list
Fix typo in old changelog.
Move module import side-effects in celery.tests to a unittest setup function.  Closes #1237
Move module import side-effects in celery.tests to a unittest setup function.  Closes #1237
Fixes docstring
Use the timer for rate limits when on the eventloop (amqp/redis)
AsyncTaskBucket: Support changing limits at runtime
Rate limit support for eventlet/gevent
kvbackends: Use save_group directly
chord()() now returns AsyncResult with .parent set, like chain
Using unittest.setup did not work well
flakes
Tests passing
Windows/execv: Import modules before calling log setup.
GroupResult.revoke now supports the terminate and signal keyword arguments
Request: Don't use __slots__ if PYPY and add __weakref__ support
timer2: Entry: Use __slots__ (if not on PyPy) and weakref for the tref link
Fixes typo