Rename the folders related to exercises.

The following 2 changes has been made:

        Answer_to_Exercise -> Exercise
	Extended_Exercises_to_Practice -> Extended_Exercises

Thank you!
							Lawrence X. Amlord
							  Oct 17th, 2013
							  Xi'an, China
Rename the folder of Extended Exercise 1.1.

The following renaming occurs:

	Extended_Exercise_1.1 -> Exercise_X1.1

Thank you!
							Lawrence X. Amlord
							  Oct 17th, 2013
							  Xi'an, China
Add the problem Extended Exercise 1.2.

Included is the following file:

	Exercise_X1.2.tm

Thank you!
							Lawrence X. Amlord
							  Oct 17th, 2013
							  Xi'an, China
Add my answer to Exercise 1.3.

Included is the following file:

	Exercise_1.3.tm

Thank you!
							Lawrence X. Amlord
							  Oct 17th, 2013
							  Xi'an, China