Update README.mkd: Missing `relay_enabled` Change from Merge #6

Whoopsies!  Forgot to mark `relay_enabled` as `False` in #6.  Guess a commit change went missing.

Reason (from #6):
* [Suggested - Provided Conf Change] Set `relay_enabled` to `False` by default in the example config - this is done because it might not be a good idea to turn it on by default until the configuration has been set up and tested.