And-facts only supported for rule lhs, not for statements.

I can write rules like "?x likes ?z when ?x likes ?y and ?y likes ?z", but I can't state "Anna like Bob Smith and Bob Smith likes Carol", I have to make one statement after the other. This is because each statement must be checked to see whether it's already known, or the opposite is known. Currently the bot simply asks the user to make the statements separately.