text: Title: pandasgui shutdown out of interactive cmd, pandasgui.show(df, settings={'block': True}) is needed.
  Body: Hi @adamerose ,
  
  I am trying pandasgui in some python script, unlike in interactive cmd, it shutdown immediately after running.
  I find `settings={'block': True}` is necessary, would you please figure it out in the demo examples?
  Thank you and pandasgui is nice tool!
  
  