* Add icons variants for required resolutions
* Optimize PNG's size
Even without centralizing the resources, we can already save a few bytes.
The total size was reduced by 75%.
* Replace iTunes variants by a very compact transparent image
This will never hit the AppStore anyway.
* Replace images by lossless optimized variants
The previous optimization pass was lossy. This PR replace images with an optimized lossless variant of the original.
* Restore original iPhone icons
I don't know why images that were supposedly losslessly optimized by ImageOptim were less vibrant than the original.
I restored them by their original variants. Upscaled variants are less vibrant though, but I guess it's acceptable without access to the original vector source.
* Fix color space
ImageOptim seems to change the color space when it optimizes files losslessly.
I've created new variants with Pixelmator Pro and exported as web-compressed from there instead.
