get for UArray blows the heap for large arrays

``` haskell
instance (Binary i, Ix i, Binary e, IArray UArray e) => Binary (UArray i e) where
get = do
bs <- get
n <- get
xs <- getMany n
return (listArray bs xs)
```

getMany is fully strict in the list, since it uses an accumulator and reverses it at the end. The intermediate xs list can be huge in cases where the eventual UArray is much more manageable (eg 28M Booleans).

Two questions:

1) Is there a known alternative for (un)serializing UArrays to(from) disk? Such an alternative would make this Issue far less important.

2) Have you considered a version that serializes the bytes directly? I drafted one up; it's tremendously more efficient, though I'm concerned about robustness wrt endianness etc. Furthermore, it requires a base monad that can mutate arrays, which requires an "unsafe" invocation. And lastly it's not portable, using ghc-prim.

HTH. Thanks.

Comienza con la instancia get de Binary (UArray i e) y su ruta getMany, reproduciendo la decodificación de un Boolean UArray grande para medir el uso de memoria de la lista intermedia. Revisa el enfoque direct-byte propuesto frente a endianness, mutabilidad, portabilidad de ghc-prim y las alternativas de serialización en disco. Se considera terminado cuando haya un alcance acordado y una ruta de serialización de UArray probada que evite el crecimiento descontrolado del heap.

Escrito por el modelo de indexación a partir del texto del issue.