Add unit tests for internal functions in used in the aggregator
Remove old shepherd designation
Improve TestInitialize

- Make initializeTimeout a package-level var, from previous const 1s
- TestInitializeSuccess (don't care about details)
- TestInitializeFailure, recovering from expected panic
Move factory method for creating state machine in every tests
Merge branch 'aggregator-unit-tests' of ssh://github.com/soundcloud/harpoon into aggregator-unit-tests

Conflicts:
	harpoon-scheduler/neu/remote/aggregator_internals_test.go
Merge pull request #91 from soundcloud/aggregator-unit-tests

Add unit tests for internal functions in used in the aggregator