really really add a third (fourth if counted from 0) mipmap level
sampler-lohalo: max all mipmaps out
sampler-lohalo: incorrect factors in mipmap weights
sampler-lohalo: code refactoring for clarity
cosmetic
cosmetic
sampler-lohalo: repetitive code -> macro
sampler-lohalo: init higher mipmap levels
lohalo-sampler: shorter code
lohalo-sampler: shorter cod
sampler-linear: (temporary?) extra safe context_rect
sampler-linear: add extra elbow room through #define
sampler: increase elbow in bilinear, use mipmap 0, set max width and height through #define
revert changes made to quickly track bug
transform-core: align the who owns halfway between pixels convention in bounding box computation (and update test image results)
transform-core: revert to the 'better' bounding box
add positional seeded noise to noise-rgb
random: ensure we pick different primes

With three levels, picking the same prime twice would cancel out two of the
tables.
random: significantly reduce memory use

we still generate terabytes big space of random data on demand.
transform-core: force w to be positive without losing track of what it should be