non-recursive library to find permutations, combinations, product

Both Algorithms are searching for the permutation without repetition of n different digits i.e. n=3 [0, 1, 2] [0, 1, 3] ... [0, 2, 9] [0, 3, 1] [0, 3, 2] ... [9, 8, 6] [9, 8, 7]

To compare Backtracking and Linear Algorithms you can run "ant test" in your console (on my machine it works a minute).

ant jar creates a library and puts it to the release folder

• Release 0.0.2

Added Backtracking.permutations and Backtracking.product methods

	String[] p_without_repetitions = Backtracking.permutations(new String[]{"A","B","C","D"}, 2);
	System.out.println(Arrays.toString(p_without_repetitions));
	String[] p_with_repetitions = Backtracking.product(new String[]{"A","B","C","D"}, 2);
	System.out.println(Arrays.toString(p_with_repetitions));
	String[] combinations = combinations(new String[]{"A","B","C","D"}, 2);
	System.out.println(Arrays.toString(combinations));

• Release 0.0.3

Added Backtracking.combinations and Backtracking.is_sorted methods

------------------------------------------------|-------------------------------------------------- permutations(new String[]{"A","B","C","D"}, 2); | [ A B , A C , A D , B A , B C , B D , | C A , C B , C D , D A , D B , D C ]
product(new String[]{"A","B","C","D"}, 2); | [ A A , A B , A C , A D , B A , B B , B C , B D , | C A , C B , C C , C D , D A , D B , D C , D D ] combinations(new String[]{"A","B","C","D"}, 2); | [ A B , A C , A D , B C , B D , C D ]