more fiddling with hackage docs script
probably not going to ever use the HPair and Pair, but updating docs headers for now
snapshot  of one design choice for the array builder design, will probably shift to something closer to the Stream/Bundle type used in Vector though
Substantially improved Batch Initializer structure. In some sense  this design is a simplified analogue of the Stream type in Vector,
but specialized to the two common cases.

One design question is whether
newtype IntFun a = Ifun  (forall m. (PrimMonad m,Functor m )=>  Int -> m a ) is correct
or if it should be newtype IntFun a = Ifun  (  Int -> a ). Taking the monadic route for now.