Bump to 0.3.0
Implement global task registration

Instead of requiring the caller to declare a VService subclass with
TASKS, you can now instead call Task.register() on all the necessary
tasks, and use the default VService implementation for starting your
service.

e.g., before:

  class MyTask(PeriodicTask):
      # blargh

  class MyService(VService):
      TASKS = [MyTask, ...]

  MyService.initFromCLI()

You can now do:

  class MyTask(PeriodicTask):
      # blargh

  MyTask.register()
  VService.initFromCLI()

It is smaller!