Sample: remove is_control property
Fix Test Sys-sw not doing what was intended.
Revert "update diag() code on diff failure for Strelka"

This reverts commit 45073ff67d47621fd73bae4a4f43f4211bf7b838.
rename $exit_code variable to $sytem_retval, since this another variable actually contains the exit code
updated "genome model copy" to support input_model.other_input_model.blah=foo, and recursively make new underlying models as needed