special 0.2.0

The library provides special functions.
Documentation
# Special Functions [![Build Status][travis-svg]][travis-url]

The library provides [special functions][1] and currently includes:

* `erf` — the error function,
* `erfc` — the complementary error function,
* `inc_beta` — the incomplete beta function,
* `inv_inc_beta` — the inverse of the incomplete beta function,
* `ln_beta` — the natural logarithm of the beta function, and
* `ln_gamma` — the natural logarithm of the gamma function.

## [Documentation][docs]

## Acknowledgments

The code is based on [libm][2] and the work of [John Burkardt][3].

## Contributing

1. Fork the project.
2. Implement your idea.
3. Create a pull request.

[1]: https://en.wikipedia.org/wiki/Special_functions
[2]: https://sourceware.org/newlib/libm.html
[3]: http://people.sc.fsu.edu/~jburkardt/

[travis-svg]: https://travis-ci.org/stainless-steel/special.svg?branch=master
[travis-url]: https://travis-ci.org/stainless-steel/special
[docs]: https://stainless-steel.github.io/special