added optional effective adjective for visible and invisible object properties
added a test to see if parent is a group… hiding a stack doesn't change the effective visible
Merge branch 'release-6.0.1'
Update submodules.
Merge branch 'feature/effective_visible' of https://github.com/montegoulding/livecode into feature-effective_visible
Minor edits and added referencing comment (EffVisible).
Merge branch 'feature-effective_visible' into develop