Support for image reading and writing of Repa arrays using in-place FFI calls

The repa-image library adds support for reading and
writing images in many formats based on the DevIL
open source image library. Image data is represented in Haskell
as typed, multi-dimensional repa arrays.

Developer's Image Library (DevIL) is a library to
develop applications with very powerful image
loading capabilities, yet with a relatively simple
interface. DevIL can load, save, convert,
manipulate, filter and display a wide variety of
image formats, including:
    BMP, ICO, JPG, PNG, PNM, TGA, TIF, GIF, EXIF and many more.

References:
* <http://hackage.haskell.org/package/repa>
* <http://openil.sourceforge.net/>
* <http://www.haskell.org/haskellwiki/Numeric_Haskell:_A_Repa_Tutorial>