Merge branch 'master' into add_batcher_example

* master:
  Fixed typos in the comments and the Exception. Also fixed if condition to check registry
  Remove get_messages call as the MessageIterator does what's needed.
  removing further reference to _executing_async in get_current_context
  Add MessageIterator for pulling work off a pull queue.
  Adding get_current_context() method
Add basic error handling for start on Async.

Switch the insert task logic in Async.start to match the context insert_tasks
function by handling some standard queue exceptions.
Update batcher default queue to proper name.
Add batcher.Message to context.add check

Add batcher.Message to the context.add isinstance check to allow batch inserts
of Messages similar to Asyncs.
Add batcher example to examples

Created a batcher example that allows the insertion of many messages and batch
processing of those messages.
Merge branch 'master' into add_batcher_example

* master:
  Fix test comment for test_async
  Add module docstring to example/runner.py
  Have Async.start retry on TransientError
  Add docstrings to the example/runner.py module.
  Add basic error handling for start on Async.

Conflicts:
	furious/async.py
Re-order the imports to make Robert happy :)
Clean up some of the batcher example and switch the caching to CAS
Clean up the batcher example html and javascrpt
Merge pull request #31 from beaulyddon-wf/add_batcher_example

Add batcher example