Overhauled ES wallpapers

[Jaffacakelover]

Corrected spelling of folder (from 'blured' to 'blurred'). ADDED several new wallpapers, for cores that generate playlists. ADDED Retroarch.png to use as default background. ADDED duplicate images for Wii (Digital), PSP (Digital) etc. ADDED source images (and readme list) for all wallpapers. RESIZED all to 16:9 and 4:3 ratios, at 1080p.

REPLACED wallpapers:

• Amstrad CPC: Was Rick Dangerous II (Atari ST), now Rick Dangerous (Amstrad CPC).
• Commodore 64 - Was Ultima IV, now Wizball.
• GCE Vectrex: Was Cosmic Chasm (Arcade), now Spike (Vectrex).
• Oddyssey2: Was K.C. Munchkin (Atari 7800), now K.C. Munchkin (Oddysey2).
• Nintendo DS: Was Mario Kart 7 (3DS), now Kirby Canvas Curse (DS).
• Sega CD: Was Sonic CD, now Snatcher.
• Sony PSP: Was Monster Hunter Portable 3rd, now Patapon 2.

RENAMED Quake 2.png to Quake II.png RENAMED Quake 3.png to Quake III.png

[baxysquare]

This PR has had two years to be reviewed. If there are no objections, I will merge it in the next day or two.

[Jaffacakelover]

All of these wallpapers are of differing sizes. Is there a way to have a consistent size for them? Like 1280x720 or 1920x1080 or something?

A deliberate choice, to have images in the source folder at the original system's resolution where possible. The images in the "main" folder have been unified at two resolutions and put into subfolders.

[Jaffacakelover]

If needs be, I could save the source images off in a little repo of their own and delete them from this one.