Nolds

Added
- nolds now lists numpy as dependency (it had the dependency before, but did not tell the user, because who the hell uses python without numpy ;P)

Added
- initial release including the following algorithms:
- sample entropy (`sampen`)
- correlation dimension (`corr_dim`)
- Lyapunov exponent (`lyap_r`, `lyap_e`)
- Hurst exponent (`hurst_rs`)
- detrended fluctuation analysis (DFA) (`dfa`)