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))