Fixed some config issues

Binary assets

xmrig-v2.6.4-mo2-win64.zip
xmrig-v2.6.4-mo2-lin64.tar.gz

Changes

• Removed "cn-fast" from "threads" since it uses the same thread setup as "cn"
• Allowed to use integer numbers as "algo-perf" values

xmrig v2.6.4 with algo switching support

Binary assets

xmrig-v2.6.4-mo1-win64.zip
xmrig-v2.6.4-mo1-lin64.tar.gz