Add the code in section 4.2.2.

Included is the following file:

	4.2.2_An_Interpreter_with_Lazy_Evaluation.scm

Thank you!
							Lawrence X. Amlord
							  Feb 20th, 2014
							  Fuzhou, China
Implement The Lazy Evaluator.

Included are the following 2 files:

	Lazy_Evaluator.scm
	Test_for_Lazy_Evaluator.scm

Thank you!
							Lawrence X. Amlord
							  Feb 20th, 2014
							  Fuzhou, China
Add my answer to Exercise 4.27.

Included are the following 4 files:

	Exercise_4.27.pdf
	Exercise_4.27.scm
	Exercise_4.27.tm
	Lazy_Evaluator.scm

Thank you!
							Lawrence X. Amlord
							  Feb 21st, 2014
							  Fuzhou, China