code: public void bindExternalFunction(String funcName, ExternalFunction func) throws Exception {
  		ifAsyncWeCant("bind an external function");
  		Assert(!externals.containsKey(funcName), "Function '" + funcName + "' has already been bound.");
  		externals.put(funcName, func);
  	}
docs: Most general form of function binding that returns an Object and takes an
  array of Object parameters. The only way to bind a function with more than 3
  arguments.
  
  @param funcName
  EXTERNAL ink function name to bind to.
  @param func
  The Java function to bind.