Add sequence stop on not finding more events to process

[fdplacido]

BEGINRELEASENOTES

• When indicating to process more events than available, algorithm will create empty event and fail by trying to continue.
• If no more events to read are found, the processing will stop
  ENDRELEASENOTES

[fdplacido]

Fixes #36

[tmadlener]

Hi @fdplacido,
Thanks for taking care of this. Looks good to me.

I have two minor questions that only concern the tests: Wouldn't it be possible to run the tests via k4run [...] --num-events=[number of events]? In that way only one options file and bash script would be necessary to cover both currently present tests. Also I think it would be nice to add a comparison of the number of events in the input file and the output file via lcio_event_counter (just to be really sure that there is no empty event).

[fdplacido]

I changed it to use k4run as you suggested. For the number of events comparison: I agree, that is a good test to have, so I'll create a simple options file that creates some output to be able to compare.

[fdplacido]

I added a test to check that using lcio_event_counter, thanks for the suggestion @tmadlener

[fdplacido]

I updated as you suggested, checking now for correct number of output events with -1, and testing for any number of events.

[andresailer]

Looks good to me