An efficient implementation of Int-indexed arrays (both mutable and
immutable), with a powerful loop fusion optimization framework.

It is structured as follows:
* Data.Vector
    Boxed vectors of arbitrary types.
* Data.Vector.Unboxed
    Unboxed vectors with an adaptive representation based on data type
    families.
* Data.Vector.Storable
    Unboxed vectors of Storable types.
* Data.Vector.Primitive
    Unboxed vectors of primitive types as defined by the primitive
    package. Data.Vector.Unboxed is more flexible at no performance
    cost.
* Data.Vector.Generic
    Generic interface to the vector types.