SetVariable issue in bimlStudio

Documentation on docs.varigence.com suggests that adding dependencies to the SetVariable activity is supported. However, BIML Studio 5.0 Intellisense does not suggest you can, and if you add it anyway, the build fails. Obviously, you need to be able to have a dependency when using this activity. 

Thoughts?

This is unexpected behavior. 

`SetVariable` and `AppendVariable` have been fixed, and users can now create these activities with their dependencies collections included.