Improved user-specified abort conditions

[KOVALW]

Rather than terminating on the first death, there should be an improved run stop variable that users can quickly use for specifying termination behavior. For example, this may look like:

{..
  "termination_conditions": {
    "first_n_deaths": {
      "abort_run_when_met": true,
      "n": 1
    },
    "first_n_hospitalizations": {
      "abort_run_when_met": false
    }
  }
}