Changes in version 0.1.5                        

  - Fixed the multiple-life Monte Carlo workflow used in the
    mc_annuity() examples.
  - simulate_lifetimes() now constructs lifetime simulations defensively
    when mortality inputs contain invalid terminal values.
  - mc_multilife_status() now uses defaults compatible with
    simulate_lifetimes(): sim_id, life_id, Kx, and Tx.
  - Added a regression test for the full multiple-life simulation
    workflow.