Start to split context into modules for clarity and extensibility.
Split ExecutionContext and associated logic into module.

Move ExecutionContext to a separate module since it is not intended for
general consumption, but is rather an internal structure.
Split the base Context object into its own module.

Move Context into its own module to make the code easier to follow and
understand the purpose of each type of context.
Update processor tests for new ExecutionContext path.
Create context package init to hold top level public API.
Update local context notes and clarify naming.
Remove remaining context module cruft.

All context code is now split up and living in the context package.
This was done to help make usage more clear.
Move new context test to the context test in the context test package.
Merge pull request #14 from WebFilings/context-breakup

Splitting context module into a package to clarify usage.
Bringing the readme up to date with the current code.
Add note about working examples to readme.
Removed extra _ in on_complete note.
Improve note about Context.on_complete.
Make sure public API methods are imported into context.
Merge pull request #16 from WebFilings/context-splitup-import-fix

Make sure public API methods are imported into context.
Merge pull request #15 from WebFilings/readme-cleanup

Readme cleanup
Add batcher module and Message object

Add the batcher process module with the Message object that wraps tasks
inserted into the pull queue.
Add queue.yaml with default and defualt-pull entries.

Also update the batcher module to use the defualt-pull queue by default.
Remove unneeded comment in batcher unit test.
Merge pull request #18 from beaulyddon-wf/add_batcher

Add batcher module and Message object