Add option to stop processor when error is raised

[jiexinhuang]

Instead of retry processing, sometimes we would like to stop the processing pipeline in case of failure. This PR adds a options to ESPRunner so event processor can die when a exception is raised.

Note

As it is a option with default value, this change should not break current public interface.

[stevehodgkiss]

Would an exponential retry backoff be more appropriate? Or a configurable x number of failures until giving up (to account for transient failures)?

[jiexinhuang]

@stevehodgkiss I love that idea, but it will also change current behaviour. Sounds like a feature to add for the next major version! 😄