baselinestretch updated
small modification to report
updated plan
updated
typo correct
Merge branch 'master' of https://github.com/wqfish/avl

Conflicts:
	report/report.pdf
Part 5 modification
Merge branch 'master' of https://github.com/wqfish/avl

Conflicts:
	report/report.pdf
updated
Merge branch 'master' of https://github.com/wqfish/avl
Remove debug print
Little modification on parser.y and syntax_tree.h
Try todo
Typechecking phase 2.1
Typechecking: phase 2.1, bug fixes
Type checking, phase 2.2, compilable
Remove debug file.
Delete debug printf.
But fixes.