0.3

Extensive, backwards-compatibility breaking redesign.

• This library no longer uses subclasses. Instead, a Registry() object is created and async def functions are registered with that registry. The registry.resolve(fn) method is then used to execute functions with their dependencies. #8
• Registry(timer=callable) can now be used to register a function to record the times taken to execute each function. This callable will be passed three arguments - the function name, the start time and the end time. #7
• The parallel=True argument to the Registry() constructor can be switched to False to disable parallel execution - useful for running benchmarks to understand the performance benefit of running functions in parallel. #6