Changed permissions of prefsCleaner.sh from 644 to 755 to be able to run it via "./prefsCleaner.sh" with out first executing "chmod +x prefsCleaner.sh".
- add -s parameter to start immediately / skip prompt / run non-interactive
This is useful if the user wants to automate the process of updating the user.js and cleaning prefs.
- fQuit: error messages to stderr
- fFF_check: info msg to stderr
Better support for suppressing/redirecting stdout while still showing any error messages in the console, useful for example with `prefsCleaner.sh -s >/dev/null`
