Webicon PNGs should be optimised

[coliff]

Losslessly optimising the PNGs would save ~71kb, reducing the file size of the images by 20% on average and the images would look identical with no loss in quality.

Use Imageoptim on OS X or PNGGauntlet on Windows to losslessly optimise the images.

[dandv]

I don't think this project is being actively maintained.

[adamfairhead]

@dandv Been incredibly busy :) He's absolutely right about compression.

The repo will benefit from a few difference updates, thanks for reminding me @coliff!