The full benchmark can now be launched with "ccminer --benchmark"
add a new helper function which log a warning with last cuda error
(not shown with the quiet option) : CUDA_LOG_ERROR();
it can be used where miner.h is included (.c/.cpp/.cu)
fix x14 (in ccminer.cpp), a break was missing in switch..case
0: cudaDeviceScheduleAuto
1: cudaDeviceScheduleSpin
2: cudaDeviceScheduleYield
4: cudaDeviceScheduleBlockingSync
Also set the best one (4) for luffa algo by default...