set lexeme info for all token
fix lineNum error with block comment
Monster test
leave Comment.java a legal minijava source
parser complete
add more diagnositc message
add Lab2 part B test log
init Lab2
Lab2 Exercise 3
Lab2 Exercise 4
Lab2 Exercise 5. Part A complete
Lab2 Part B complete
Lab2 Part B complete
Merge branch 'Lab3' into Lab2

Conflicts:
	src/elaborator/ElaboratorVisitor.java
modify dump(), circular inheritance, NotExp
Lab3 init
Lab3 init
C gen complete
Lab3 part A complete
Lab3 part B finished