**_One of the Best Medieval/British Isle flicks_** Remember the three such movies of 1995: "Braveheart," "Rob Roy" and "First Knight"? "Tristan + Isolde" is better than all of them or, at least, on par. It shares plot elements of "First Knight" with the king's trusted protégé playing around with his young wife, but "Tristan + Isolde" is just ove…