add option `unroll` for OpenCL to allow better tuning the main POW kernel.

Create a special pass for NVIDIA GPUs to load memory chunks first into the shared memory.

Co-authored-by: SChernykh <sergey.v.chernykh@gmail.com>

- use shared memory to exchange

implement `cryptonight_v8`

- implement cryptonight_v8
- update auto adjust to fit the special requirements of `cryptonight_v8`
- add fast math integer implementation for `sqrt`, `reciprocal`  and `division`

Co-authored-by: SChernykh <sergey.v.chernykh@gmail.com>

Add support for single hash cryptonight_v8.

Co-authored-by: SChernykh <sergey.v.chernykh@gmail.com>

- rmeove currency `monero7`
- introduce `cryptonight_v8` and `monero8`

During the initialization of the compile parameter for OpenCL it could be that the
fixed size buffer is to small. To avoid this we are now using `std::string`.
There is no problem by using `std::string` because this part of code is not perfromance critical.

If the first bit of the nonce is `1` (this is very often if we use a nicehash pool)
than it could be that some OpenCL implementations handle the 64bit representation of the 32bit
nonce on the device side as signed integer.
During a right bitshift we pull wrong ones from the wrong higher part of the 64bit
nonce representation into the 32bit part of the nonce.
The result will be that the computed share is invalid.

- explicit cast the nonce on the device to `uint` to avoid any side effects

Avoid that a OpenCL binary from the cache is used if the driver or xmr-stak version has changed.

There is a copy past mistake tha tthe type of the variable `memChunk` is not tested.

xmr-stak has several implementations for multi hash per thread.
The results into 3 intepedent implementations.
Each time the algorithm must be changed the possibility to introduce errors is very large.

- unify the different cryptonight CPU implementations
- simplify the function selection array to find the specilized cryptonight implementation
- add a intermediat pointer to access the large state (similar to the old multi hash implementation)

As side effect this change increases the speed of the single and multi hash algorithm.

The most algorithm currently are not checked in the cpu self test function.

- add hash for each algorithm

OpenCl 1.2.is not allowing the subscript operator on buildin vector types.

fix: use `.sX` to access vector components

5% more hash per second

- add cryptonight_heavy derivate cryptonight_bittube2
- add coin bittube
- remove coin ipbc because this coin is now called bittube

fix #1708

The extension of the job result contains the wrong algorithm used to create the nonce.
The fix provide now the correct used algorithm even if the coin is forking to a new algorithm.

- forward the used algorithm from the miner

- explicit loop unrolling

based on changes in @imperdin fork https://github.com/imperdin/xmr-stak/blob/master/xmrstak/backend/amd/amd_gpu/opencl/cryptonight.cl

- update pools.txt
- add new algorithm `cryptonight_haven`
- update all backends

- rename cryptonight_fast to cryptonight_masari
- set dev pool to cryptonight_monero

The define of `_mm256_set_m128i` is not needed and avoid intel compiler throws a warning about it.

- avoid that a nonce which not fits to the current job is used (check jobId after start nonce is consumed)
- move jobId check into the if condition to get a new bunch of nonces
- CPU: add jobId validation after the start nonce is consumed

If CUDA 9.X is used and the miner is compiled for `sm_70` and used with Volta GPUs than the miner
deadlocks if `threads` is not a multiple of `32`.

- use `__activemask()` to get all active lanes

- reformat `read_write_lock.h`
- fix spelling issue
- move job id increase of the write to the buttom

user read write locks to be sure that no job is consumend during the job update

add log class from Will Zhang:

Package: cpputil
Source: https://github.com/willzhang4a58/cpputil
License: MIT License

fix #1505

- fix possible deadlock of the executor thread
- fix racecondition during the job consumation
- remove switch_work in all classes `minethd`
- move `consume_work` into `globalStates`

- initialize miner_work iPoolId in the default constructor with the invalid pool id
- move definition of `pool_data` into an own file

solve #1494

- add algorithm `cryptonight_v7_stellite` (internal named: `cryptonight_stellite`)

- add algorithm `cryptonight_lite_v7_xor`
- update documentation

- fix that to much OpenCL calls whre used if cache is disabled

remove fork version for sumokoin and monero7

- allow the dev pool to fork on a different block version than the user descriped coin

All algorithm are centered around the user coin description.
It is allowed to have two two different coin algorithms in the user coin description.
It is only allowed to use algorithms for the dev pool coin description those are used in the user coin description.
There are two ways to define a non forking coin.
  - set both user coin algorithm descriptions to the same algorithm and set version to zero
  - set the first algorithm in the user coin description to something you like to use in the dev pool
    and set the second algorithm to the correct representation of the coin. Set the version to 255.
    This will allow that the dev pool can mine on a different coin algorithm than the not forking user coin.
    Do not use an algorithm with different scratchpad size for the dev pool.

In the case where the dev pool mines on a higher version than a monero fork coin the miner is not resetting the algorithm.
This PR select the correct algorithm each time the block version hash changed.

- add CLI flag to explicitly use non AMD OpenCL and devices
- adjust OpenCL output (use OpenCL instead of AMD if --altOpenCL is sued)
- optimize NVIDIA OpenCL auto suggestion