Various Improvements

[easrng]

This PR

• adds support for ScratchStatus
• Tweaks the CSS (slight changes to the buttons, fixes the footer on small screens)
• Improves the dev experience (It now works when it's in a subfolder and when you load it with #noproxy as the hash it skips the CORS proxy)
• Fixes #32 (updates the pin tab gif, now with a version for Firefox too)
• Fixes #16 (Handles background loading errors)
• Switches the source of backgrounds to Unsplash for higher quality and adds HiDPI (retina) support
• Removes the reference to the removed mobile site

[Shluffy]

@ZI-Youtuber your approval will do nothing