3DS: Improve sharpness of non-integer scaling modes.

[asiekierka]

This is what we do in the TIC-80 port.

I use the GPU (which is not very busy, admittedly) to scale the 240x136 TIC-80 display to 720x408 (3x integer), then scale that down as necessary. This improves the sharpness of the resulting non-integer scaled output.

This helped sharpness in our case; I am not sure how much it will help with FAKE-08.