Problem Set 4 done, with Problem 4 & 5 solved.

Augmented are the following 4 files:

	Assignments/Problem_Set-4/ps4/src/sat/SATSolver.java
	Assignments/Problem_Set-4/ps4/src/sat/formula/Formula.java
	Assignments/Problem_Set-4/ps4/src/sudoku/Main.java
	Assignments/Problem_Set-4/ps4/src/sudoku/Sudoku.java

Thank you!
							Lawrence X. Amlord
							  Nov. 5th, 2014
							   Xi'an, China