Group Images folders by scraping platform name, rather than imported platform name

If you rename a platform later, or you're importing multiple groups of the same platform (just titles slightly differently, you get a huge amount of overlap.

It'll just benefit anyone like me, who keeps, for instance, separate Atari 2600 roms by PAL/NTSC, since Mame (any other emulators) needs different drivers per video type, etc.

I know I can change them after, but it's not very easy/intuitive doing this later on.