JPG and PNG decoder

[cal]

I've been working on decoders for simple (baseline) JPEG and 
PNG's, mostly for my own amusement, and they seem to work ok now, 
so if anyone has need of some simple D modules to load these 
formats you can grab them here:
https://github.com/callumenator/imaged

Notes:
- Will load 8-bit baseline sequential JPEG's only. All PNG image 
types are supported (only critical chunks are decoded however).
- Can load from a stream or a file. In the case of the PNG's, 
this allows progressive display with an interlaced image.
- I haven't put much effort into speeding up these routines, and 
have not tested the JPEG decoder extensively, so there are bound 
to be bugs and there is plenty room for improvement.
- The example shows stream usage, and uses Adam Ruppe's 
simpledisplay to make a little viewer, that can flick through all 
images in a directory.

Cheers,
cal