Incorrect intensities with CcminerAlexis78 on GTX1080ti
I am referring to https://github.com/MultiPoolMiner/MultiPoolMiner/issues/1702 & https://github.com/nemosminer/ccminerAlexis78/releases

I get the following error when running your miner on a **GTX 1080ti:**
```
ccminer.exe -a x17 -o stratum+tcp://europe.mine.zergpool.com:3737 -u 1GPSq8txFnyrYdXL8t6S94mYdF8cGqVQJF -p BlackBox,c=BTC
*** ccminer alexis-1.0 for nVidia GPUs from alexis78@github ***
*** Built with VC++ 2013 and nVidia CUDA SDK 7.5 (Recommended)

*** Based on tpruvot@github ccminer
*** Originally based on Christian Buchner and Christian H. project
*** Include some of the work of djm34, sp, tsiv and klausT.

[2018-05-13 14:07:31] Starting on stratum+tcp://europe.mine.zergpool.com:3737
[2018-05-13 14:07:31] NVAPI GPU monitoring enabled.
[2018-05-13 14:07:31] 1 miner thread started, using 'x17' algorithm.
[2018-05-13 14:07:31] Stratum difficulty set to 0.1
[2018-05-13 14:07:31] x17 block 266654, diff 819.700
[2018-05-13 14:07:31] GPU#0: Intensity set to 22.5, 6291456 cuda threads
[2018-05-13 14:07:32] GPU#0: result for 00000006 does not validate on CPU!
[2018-05-13 14:07:32] GPU#0: an illegal memory access was encountered
Cuda error in func 'quark_blake512_cpu_setBlock_80' at line 547 : an illegal memory access was encountered.
```

It appears that the miner is using incorrect default intensity (22.5). If I **change it to '-i 21.5'** the miner runs very well.

Other algos report the same problem:
The same goes for **C11**. Default intensity 22 is too high -> **lower intensity to 21.5**.
The same goes for **X11evo**. Default intensity 22 is too high -> **lower intensity to 21**.
