Feature Request: grid filter for handhelds

[kerunaru]

While scanlines are awesome for the majority of the systems, it feels more natural having a grid filter for handhelds like Gameboy or Neo Geo Pocket instead.

I know this was mentioned on ReplayOS Official Telegram Group and @rtomasa discards this implementation but maybe he could change his mind if the feature is highly demanded.

[limi]

Co-signing this. It’s weird to play handheld systems with CRT-style scanlines, and playing them without any effects looks even worse. A simple LCD-style grid implementation would be great for all the handheld console cores.