Sleepecg

Added
- Example containing code used for benchmarks ([22](https://github.com/cbrnr/sleepecg/pull/22) by [Florian Hofer](https://github.com/hofaflo))

Changed
- Shorten names of some functions and modules ([18](https://github.com/cbrnr/sleepecg/pull/18) by [Clemens Brunner](https://github.com/cbrnr) and [Florian Hofer](https://github.com/hofaflo))
- Separate reader functions per database ([32](https://github.com/cbrnr/sleepecg/pull/32) by [Florian Hofer](https://github.com/hofaflo))
- Use `~/.sleepecg/datasets` as default `data_dir` for readers ([33](https://github.com/cbrnr/sleepecg/pull/33) by [Florian Hofer](https://github.com/hofaflo))

Added
- Add interface to download NSRR data ([8](https://github.com/cbrnr/sleepecg/pull/8) by [Florian Hofer](https://github.com/hofaflo))
- Add pure Python and Numba implementations of heartbeat detection ([10](https://github.com/cbrnr/sleepecg/pull/10) by [Florian Hofer](https://github.com/hofaflo))

Fixed
- Fix MemoryError in case of invalid checksum ([3](https://github.com/cbrnr/sleepecg/pull/3) by [Florian Hofer](https://github.com/hofaflo))

Added
- Initial release (by [Florian Hofer](https://github.com/hofaflo) and [Clemens Brunner](https://github.com/cbrnr))