Adds image-rendering: pixelated; to all img tags

[Shrinks99]

Makes all images on the website ignore filtering to preserve their nicely dithered look.

Closes #9

[rscmbbng]

HI, thanks for your PR. I've tried it but I find that the crisp rendering looks pretty awful since interpolation happens anyway as images are stretched to 100% (often beyond the original resolution of the dithered image). So this would work for viewing images at exactly 100% of the res, but above or below that the current rendering method is much better.

[Shrinks99]

I'm not convinced that it looks better blurred but hey, that's an argument about personal preferences and it's your website so to each their own! Have a good one :)