ReaderFactory doesn't support reading from stdin in 3.3.0

The convert_example.cc from the examples suggests that it should be possible to cat some events into stdin and use the ReaderFactory with this, but in practice this crashes on the first event, e.g.

WARNING::ReaderAscii: skipping unrecognised prefix: 6
ERROR::ReaderAscii: particle ID is out of expected range.
ERROR::ReaderAscii: event parsing failed. Returning empty event

as an example.

If I disable the auto-detection and pipe the events directly into the ReaderAscii, it still works fine though.