Add addaptive algorithm

rtree/src/Control/Monad/IRTree.hs

rtree/src/Control/Monad/RTree.hs

rtree/src/Data/RPath.hs

rtree/test/expected/double-let-expr-ired

rtree/test/expected/double-let-expr-ireda

rtree/test/expected/double-overloading-let-expr-ired

rtree/test/expected/double-overloading-let-expr-ireda

rtree/test/expected/small-let-expr-ired

rtree/test/expected/small-let-expr-ireda

rtree/test/expected/small-opr-expr-ired

rtree/test/expected/small-opr-expr-ireda

rtree/test/src/Control/Monad/IRTreeSpec.hs

rtree/test/src/Control/Monad/RTreeSpec.hs