Changes for PDL::IO::Image

0.003   2014/12/09
        - requires Alien-FreeImage-0.011 (-fPIC issue)
        - void methods return self: $pimage->save("im.png")->save("im.bmp")->save("im.gif")
        - new methods: color_dither, color_threshhold, color_quantize
        - pod fixes

0.002   2014/12/09
        - initial version