added eq_file / copy_file corresponding to File.eq / File.copy in ML;
added eq_file / copy_file corresponding to File.eq / File.copy in ML;

MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle,MerelyAPseudonym/isabelle