Final bug fixes.

Worklog.
Added test diff.py demonstrating the differences between the reference compiler.

src/main/java/chocopy/pa2/StudentAnalysis.java

@@ -90,7 +90,7 @@ public class StudentAnalysis {
             TypeChecker typeChecker = new TypeChecker(globalSym, program.errors);
             program.dispatch(typeChecker);
         }
-        //System.out.println(program);
+        // System.out.println(program);
         return program;
     }
 }