Wraps the given function so that the history log is saved when it is called, and then the given function
is run

@param {Mocker} mocker     The mocker object
@param {Function} fn       The function to run
@return {Function}         The wrapped function
@api public
function wrapFn(mocker, fn) {
  return function() {
    //Copy the arguments this function was called with
    var args = Array.prototype.slice.call(arguments);
    
    //Save the arguments to the log
    mocker.history.push(args);
    
    return fn.apply(this, arguments);
  };
}