Update my answer to Exercise 2.90.

Modified is the following file:

	Exercise_2.90.scm

Thank you!
							Lawrence R. Amlord
							   Aug 24th, 2013
							   Fuzhou, China
Update my answer to Exericse 2.91.scm

Modified is the following file:

	Exercise_2.91.scm

I've supplement the answer with the following testing file:

	Test_of_Exercise_2.91.scm

Thank you!
							Lawrence R. Amlord
							   Aug 25th, 2013
							   Xi'an, China
Update my answer to Exercise 2.93.

Modified are the following 2 files:

	Exercise_2.93.scm
	Test_of_Exercise_2.93.scm

Thank you!
							Lawrence R. Amlord
							   Aug 25th, 2013
							   Xi'an, China
Add my answer to Exercise 2.94.

Included are the following 2 files:

	Exercise_2.94.scm
	Test_of_Exercise_2.94.scm

Thank you!
							Lawrence R. Amlord
							   Aug 25th, 2013
							   Xi'an, China
Add my answer to Exercise 2.95.

Included is the following file:

	Exercise_2.95.scm

Thank you!
							Lawrence R. Amlord
							   Aug 25th, 2013
							   Xi'an, China
Add my answer to Subproblem-a of Exercise 2.96.

Included are the following 2 files:

	Exercise_2.96-a.scm
	Test_of_Exercise_2.96-a.scm

Thank you!
							Lawrence R. Amlord
							   Aug 26th, 2013
							   Xi'an, China
Add my answer to Subproblem-b of Exercise 2.96.

Included are the following 2 files:

	Exercise_2.96-b.scm
	Test_of_Exercise_2.96-b.scm

Thank you!
							Lawrence R. Amlord
							   Aug 26th, 2013
							   Xi'an, China