Fix for Store issue 818 - system messages not showing up

Fix for https://github.com/Rise-Vision/store/issues/818
- use "sm.slice(0)" to copy array, otherwise changes in the systemMessages are not detected
- removed duplicate reference to the "../../src/js/svc-system-messages.js"
@olegrise this watch doesn't make sense to me. In theory it will never be triggered because you are comparing ```systemMessages``` by reference, and this reference never changes once the controller is initialized.