Revert "Replaced 's->clip_sigma > 0.0' condition in zerodm.c with a static int condition that is set to False when not using padvals for bandpass."
After discussion with Scott.

This reverts commit 53b0aad86101cbd124bdc83a8ce71150698182f0.
Revert "Redirected warnings in single_pulse_search.py to stdout instead of stderr."
Changing behaviour of warnings should be handled by pipeline, not in PRESTO.

This reverts commit 70d63187f74cd4607710ea18eb071d408c28331f.