port features from lalapps_pulsar_crosscorr to lalapps_pulsar_crosscorr_v2
As recently discussed by e-mail, the old lalapps_pulsar_crosscorr should be deprecated in favour of lalapps_pulsar_crosscorr_v2, but there are apparently still features from v1 that v2 doesn't have.
Not clear yet who and when can do this, but I'm assigning to @john-whelan for the moment to coordinate this on a flexible timescale.
cc @karl-wette @ling.sun @andrew.melatos @jared.wofford @patrick.clearwater