Added a warning for Grbl 1.1 folks to the main /grbl workspace to redirect

Added a warning for Grbl 1.1 folks to the main /grbl workspace to redirect them to the 1.1 workspace since this is such a common question. It may help in the short term. Thank you again to jpadie for all the good work on the 1.1 support. If you dismiss the dialog, it will be a sticky setting and always hide itself 5 seconds later.

You’re a good man there Charlie Brown…