Fixed a bug that could crash miner if using CNV4 (R) algo
Fixed a bug that crashed miner if doing fast algo switching from CNV4 to any algo
Stales are not displayed anymore by default, added parameter --showstales which turns back on the display of stale shares
Changed --maxnosharesent default value from 15 minutes to 30
Logging is now disabled by default in the example start.bat
Added parameter --preparedata, which could pontentially make a small speed increase on weak GPU's, but also could make it worse. All algos except webchain
