JSON Updater dialog

Now, when there's a different/new JSON file on the web, the app will
display a dialog asking if the user would like to replace their current
one.  Currently, the dialog does nothing but notify them and display
"would update" or "wouldn't update" toast messages.  Need to cleanup
MainView.java to make the update work without a restart.

Also, removed "Node XX:\n\n" from the nodes' question strings.