[-] Quaternions
[X] Draw rotated pixels in src order
[X] Use atan2 at beginning and end of line.
    Interpolation in-between values
[X] Test pixel perfect 90
[ ] Fix out-of-bounds pixel set

[ ] Optimization for square images?
[ ] Fixed point computation?

# Cache
[X] Rotate per channel -> no gain
[ ] Load pixels in uint64-t
[ ] Cut image in tiles

# Quality
[ ] Interpolate using SIMD, SSE