Update README to indicate which parts of Preferences endpoint are supported
Update README to indicate which parts of Preferences endpoint are supported

kmeister2000/quickbooks-ruby,ruckus/quickbooks-ruby,harvesthq/quickbooks-ruby,troysurrett/quickbooks-ruby-187,ratbeard/quickbooks-ruby,ruckus/quickbooks-ruby,minimul/quickbooks-ruby,prtkzoom/quickbooks-ruby,kashif-umair/quickbooks-ruby,michaelcheung/quickbooks-ruby,cohendvir/quickbooks-ruby,muhammad-abubakar/quickbooks-ruby,raksonibs/quickbooks-extend,ruckus/quickbooks-ruby