0.1.6 CRAN update

What's Changed

• General updates by @billdenney in #61
• Allow zero-row supp data in combine_supp() by @billdenney in #62
• combine_supp() requires that the QNAM columns are not in the source dataset by @billdenney in #65
• combine_supp() now allows multiple QNAM values to go to the same IDVAR by @billdenney in #66
• Close #57: Enhance check_ct_data by @anajens in #67
• Close #52: Verify the uniqueness of records by key by @tamarasenior in #68
• Update build from derive by @statasaurus in #70

New Contributors

• @billdenney made their first contribution in #61
• @anajens made their first contribution in #67
• @tamarasenior made their first contribution in #68

Full Changelog: 0.1.4...0.1.6