Clean up and refactor a bit.
fixing bug introduced in previous commit
At ServiceBuilderImpl.install: check for the length of arrays against zero, instead of checking if those arrays are null.
At ServiceControllerImpl.transition, remove all double checks for a state, i.e., if the current state is STARTING or UP, it cannot be STOPPING and there is no need to check for that.

These checks were useful when they did more than check for state, now this became obsolete.