Add dualpivotquicksort (Dual-Pivot Quicksort)
Dual-Pivot Quicksort is a variation of Quicksort by Vladimir Yaroslavskiy. "This algorithm offers O(n log(n)) performance on many data sets that cause other quicksorts to degrade to quadratic performance, and is typically faster than traditional (one-pivot) Quicksort implementations." -- http://download.oracle.com/javase/7/docs/api/java/util/Arrays.html
Added license in gemspec
…nt compiler collision
Fix 1.9 compile error and add Heap#next_key method
…es. Now mark iteratively for splaytree and rbtree.