fixed broken data
	modified:   tests/aoj/q0003.py
fix problem description over amb
	modified:   forAOJ.txt
unittest for chap 2 quiz 3
	new file:   exercises/chap2/q0003.py
	new file:   tests/chap2/q0003.py
typo buff->buzz
slicing bug in q0003.py
	modified:   exercises/chap2/q0002.py
	modified:   tests/chap2/q0002.py
	modified:   tests/chap2/q0003.py
solve chap2.q0002 & q0003