Faster phi2 AVX2 +62%, AVX512 +150% on Intel CPUs. AMD Ryzen AVX2 is
YMMV due to its inferiour AVX2 implementation.
Fixed Hodl stats, rejects are still an issue since v3.9.5, git issue #237.
API can now be enabled with "-b port" or "--api-bind port".
It will use the default address 127.0.0.1.
Editorial: Short form options should only be used on the command line to save
typing. Configuration files and scripts should always use the long form
"--api-bind addr:port" without relying on any defaults. This is a general
recommendation that applies to all options for any application.
Removed obsolete cryptonight, all variants, and supporting code for more
size reduction and faster compiling.
Tweaked the timing of the CPU temperature and frequency log (Linux only).
Added some debug code to collect more info aboout low difficulty rejects,
git issue #236.