Adjust merge to exclude duplicate components

This MR adjusts the merging of sky models to exclude duplicate components (e.g., when the target model contains all or part of an A-team model). The current usage of the script in LINC is to give the target model as inmodel1 and the A-team model as inmodel2. The defaults should give the correct behavior in this case (i.e., when duplicates are found, the target ones are removed and the A-team ones kept), so the CWL files do not need to be changed. See RAP-284 for details.