Custom PPSSPP shaders

[spajdr]

Tried latest Git for changes in scanline shader, but no difference.
Truth is, i'm not sure how it should look.
Anyway spline36 upscaler shader is really slow and screen flickers.
AA color shader - speed is fine, but some parts of gfx are white.
4xHQ GLSL shader - speed is fine, no gfx errors.
Cartoon shader - speed is fine, no gfx errors.
Natural colors shader - slower and flickers.