Support for bmp and ico images

[FreeSlave]

I believe ico is crucial on Windows. ico is based on bmp and png, so bmp support is needed too.

[GrimMaple]

As with svg, arsd has reading of both bmp and ico. Unfortunately, the ico support is not added to arsd.image (I asked Adam directly), so it has to be added in somehow. I think the main problem would be that ico itself is not an image, but rather a collection of images, and I don't really know how to deal with this as of now. I will think about it later on.