test for & handling of `None` input in calculator app
Update references to start_worker.
Add timeit() context manager that allows multiple timers to be run simultaneously.
Add test for timer.timeit().
Add a warning deprecating Timer.start().
Use Timer.timeit() in random metrics generator.
Replace direct timing on Timer with EventTimer class.
Docuemnt EventTimer.start and .stop and add tests. Remove deprecation warnings from Timer.__exit__ and Timer.stop since they just add noise.
Add check for timer that hasn't been started.
Remove clumsy additional 'directly' from Timer class docstring.
Fix bug in example in Timer class docstring.
add health resource to MTNRwandaUSSDTransport
Fix a class name py.test dislikes and some reliance on global state and test ordering.
first stab at Helper interfaces for DR & SM
make a difference between DR pdu and DR content
ConfigClassName + test
going with Class instead of ClassName as the `field_type`
Merge branch 'feature/issue-830-config-class' into develop
Merge branch 'develop' into feature/issue-677-smpp-transport-msg-processing-class
work in progress