Leave a clean environment after exiting Shiny app #99
Description
At the moment, the shiny app assigns a number of variables using <<-. The results is that these objects are assigned in the global environment, are persist once the shiny app is closed. See image below for objects that appeared in the R session after a short session with MetFamily.
This is an issue because it pollutes the user's working environment. In addition, it could overwrite already existing objects (e.g. an object from the user called dataFrame).
The ideal case would be to not modify the global environment while running the shiny app. The second best scenario is to restore the environment to what it was once the app is closed (e.g. using onStop()).