[Feature/Bug] 2880x2160 Mode Wrongly Scales 320px and 640px Content, and Add User-Modifiable Horizontal Integer Option for Line Multiplier Mode

[GK6475]

In line multiplier mode, the horizontal resolution can be wrongly scaled at times, especially in 2880x2160 mode. So, it would be great to be able to set a specific multiplier for horizontal scaling, for amamorphic widescreen content and consoles that use different aspect ratios, which I imagine would range from 1x up to 9x if the option is impelmented.