corrected the maven coordination information.
copied existing code from previous work.
copied the Calculator class from previous permutation and combination tool classes, and done unit test for it.
copied the CombinationAlgorithm interface from previous permutation and combination tool classes, and done javadoc for it.
copied the Combination class from previous permutation and combination tool classes, and done javadoc and unit tests for it.
modified pom file to fix the scope of test dependencies.
copied the PermutationAlgorithm interface from previous permutation classes, and java-doc-ed it.
meanwhile change author names to lower case, and use lower case from now on.