Move foldlWithKeyWith, foldrWithKeyWith, foldlWithKey, foldlWithKey', foldrWithKey, and foldrWithKey' to Internal module.
Change Foldable imports for Internal module.
Rewrite foldl' and foldr' in terms of foldlWithKey' and foldrWithKey' respectively.
Define foldl and foldr for Foldable instance of Node.
Rewrite foldl and foldr in terms of Foldable instance.
Rewrite elems in terms of foldr.
implement the functions fromListWith and fromListWithKey
rewrite the fromList function without using uncurry
Corrected excessively lazy benchmarks.
Implement partitionWithKey.
Implement partition.
Bring forceTuple to top level.

Also rename 'forceTuple (a,_,b)' to forceTriple.
Corrected delete/view min/max functions.

They had been leaving Empty internal nodes in the tree.
Corrected updateExtremity-based functions.

They had been leaving Empty internal nodes in the tree.
Implement (!) operator.
Correct difference/\intersection type signatures.
Implement (\\) operator.
`fromAscListXX` and `fromDistinctAscList` implemented
`fromDistinctAscList` improved
`fromDistinctAscList`: Tree replaced by array