Update for R code, Add algorithm details
Update for R code, Add algorithm details

Details were added for a generalized n-queens solver implemented in R. A
reformatted version of the original algorithm used to implement the
8-queens solver was also added.

JDSWalker/n-Queens_Problem,JDSWalker/n-Queens_Problem,JDSWalker/n-Queens_Problem,JDSWalker/n-Queens_Problem,JDSWalker/n-Queens_Problem