Miranda respondsTo

__respondsTo/2 is a Miranda message for asking whether an object understands a message.

Returns a boolean indicating whether this object responds to messages with the verb verb and arity (number of arguments) arity.

The Miranda method for E-language objects is:
 * 1) If this object has a method with the given verb and arity, return true.
 * 2) If there is a Miranda method with the given verb and arity, return true.
 * 3) If the object has a matcher, return the result of invoking the matcher with the __respondsTo message. If the matcher does not match, return false.
 * 4) Return false.