Image writing formats

https://github.com/nothings/stb/blob/master/stb_image_write.h is awesome.

2015-11-23: Back from the dead!

I haven't really been looking at this until recently I got an email asking for a 64-bit version, so I disassembled the old version which I lost the source for and I recreated it from scratch.

Still plenty of things to work on, and we'll get there with time :)