0.3.0

• 373701e Merge pull request #17 from botify-labs/update/handle-schedule-activity-not-exist
• 5b748eb Update tox.ini and .travis.yml: drop builds for python2.6 and 3.3
• c2b607b Update tests.test_task: remove dangling line
• 166862e Update setup.py: require simple-workflow>=0.1.42
• d677981 Update tests.test_dataflow: mock boto.swf.connect_to_region to not require AWS credentials
• eeb461b Update swf.task #6: instanciate a model with .get_or_create()
• 2191333 Update swf.executor #6: handle schedule_failed when an activity type does not exist
• 2f9f128 Update history #6: support schedule_failed events
• cbfdaf6 Update swf.executor: refactor Executor.resume() in several methods