* Add support for Alexey Tourbin's QSORT code

See https://github.com/svpv/qsort

* Add benchmark scripts and compilation mode

Compile with `make O_BENCHMARK=1`, and run benchmarks with e.g.:
  ./misc/test/benchmark.sh ./nnn '/' '/usr/bin' '/usr/lib' > benchdata
You can then plot basic violin graphs with:
  ./misc/test/plot-bench.py benchdata

* Update style, doc, haiku support, fix lint