kernel: zuikkis' vanilla kernel added.

Changed encoding to UTF-8.

Will not build with sgminer (fix in next commit).

http://www.reddit.com/r/dogecoin/comments/1ui3bx/increase_such_hashrate_1_to_5_scrypt_tweaking/ceir5na

> It is pretty much stock, except that I have removed all the #pragma
> unrolls, and optimized the inner scrypt_core loop. #pragma unroll does
> not give any speedup here.

> The idea is to move the "if (j&1)" comparison to outside of the lookup
> loops. Then, if j&1 happens to be zero, the V[z] and X[z] loops can be
> combined to a single loop, which gives the speedup!

> This loop and the salsa function are the most important places in the
> entire source, it probably spends over 90% of time in here.. There's
> very little to be gained outside of these, I think.

> Donations: DQj4t2DFMQtXofhstouyZw1sYUKWUJn4wv

https://github.com/veox/sgminer/issues/4#issuecomment-32753290

> Most of these optimized kernels (including mine), have fixed
> lookup-gap=2. However, I have never seen anyone use any other value, for
> any GPU, so I think you could just remove the configurable value.

> Or with some #if LOOKUP_GAP==2 magic it is of course possible to make
> such source that allows any value.

> Some users have reported slightly slower hashrate with my kernel as
> well, but this could be some misconfiguration also.. If scrypt kernel
> becomes faster, you may need to lower the GPU engine clock to get full
> speed. Same as if you increase GPU clock too high, you will get a drop
> in hash rate.

> My source is free to use in sgminer. And if you diff to original you
> will see that the changes are not very big.

> Removing of #pragma unrolls helps in any GPU, in my opinion.. Current
> compilers know better when unrolling helps.
kernel: integrate Zuikkis' kernel, selectable with `--kernel=zuikkis`.

Kernel ckolivas is still the default. Needs documentation, too.