suspend event option to skip packages with a start_date, RT#83847
"Continue recurring billing while suspended" checkbox for event-triggered cancels in addition to manual ones, RT#26470"
and update suspend label in light of pkg_suspend, RT#11540
referral credits overhaul, use billing events, agents can self-configure, limit to once-per-customer, depend on any time from referred package, referred customer payment, specific packages, partial staged credits, RT#3983
event refactor, landing on HEAD!