* Impelement features listed in stated goals, possible add them under
  issue and give proper description.
* PR to add ppar into https://github.com/rust-unofficial/awesome-rust.
* `im` and `rpds` are current alternative for `ppar`. Find more
  alternatives and possibly benchmark them.
* Add dependency graph to README.md.
* License validation.
* Rustdoc, md-doc spell checking and hyper-link sanity.
* Add concurrency performance benchmark under `src/bin/perf.rs`.