Implement enum class SamplingMode feature (ex : Default / Sampling2x2 / Sampling3x3 ..)

[hinohie]

For each draw_xxx, we just select color by boolean (true / false)
We hope user can select sampling mode for each pixel.

[hinohie]

I already implement 3x3 sampliing but, It's quality is bad. I think we need to scaling up the sampling count
(OpenBS use 16 sampling and 36 sampling types)