New CohortDefinition that can check for patients present or absent in other Cohort Definitions

We have a need to check for "patients who receive more than one drug in a particular concept set" during a time period. To accomplish this, we propose a new cohort definition that can be configured with 1-N underlying Cohort Definitions, and a minAllowed and a maxAllowed configuration. The evaluated cohort would return those patients who are in the appropriate number of cohorts. If minAllowed is left null or is zero, then this would also need to return all patients who are not otherwise excluded by the configured cohorts.