Fixes needed in tiger/chap3

• The same fix should be done to ErrorMsg/ErrorMsg.java as in chap2
• Contrary to the book, Appel doesn't provide Parse/Yylex.class, so I added my own.
• Appel's makefile has -expect 3; I deleted this, since initially it is inappropriate. Students can add in whatever -expect makes sense for their parser.
• Parse/Grm.cup needs to have the declaration of parseResult deleted.
• Parse/Grm.cup needs to have the action code declaring sym deleted.

Fixes needed in tiger/chap4

• Appel doesn't provide a makefile (contrary to the book). Use the (fixed) one from chap3, or an improved version. used.
• Parse/Token.java is broken. Delete it, use the chap3 Parse/Lexer.java in place of the chap4 one, and modify Parse/Grm.cup to use the syntax_error and report_error from chap3's ParseGrm.cup.
• Parse/Grm.cup doesn't label ID for use in the action; put a name on it with a colon.
• Parse/Parse.java gets absyn the wrong way; it should be the return value from the parse.
• Appel's Parse/Yylex.class is broken; use your own or mine from chap3.
• Parse/Main.java doesn't print the absyn. This should be added.
• Absyn/Print.java has Absyn.Exp where it needs to be Exp.