**New functions**
Added [yasa.topoplot()](https://raphaelvallat.com/yasa/build/html/generated/yasa.topoplot.html#yasa.topoplot), a wrapper around [mne.viz.plot_topomap()](https://mne.tools/stable/generated/mne.viz.plot_topomap.html#mne.viz.plot_topomap). See [15_topoplot.ipynb](https://github.com/raphaelvallat/yasa/blob/master/notebooks/15_topoplot.ipynb).
**Enhancements**
- The default frequency range for slow-waves in [yasa.sw_detect()](https://raphaelvallat.com/yasa/build/html/generated/yasa.sw_detect.html#yasa.sw_detect) is now 0.3-1.5 Hz instead of 0.3-2 Hz. Indeed, most slow-waves have a frequency below 1Hz. This may result in slightly different coupling values when `coupling=True` so make sure to homogenize your slow-waves detection pipeline across all nights in your dataset.
- yasa.trimbothstd() now handles missing values in input array.
- [yasa.bandpower_from_psd()](https://raphaelvallat.com/yasa/build/html/generated/yasa.bandpower_from_psd.html#yasa.bandpower_from_psd) and [yasa.bandpower_from_psd_ndarray()](https://raphaelvallat.com/yasa/build/html/generated/yasa.bandpower_from_psd_ndarray.html#yasa.bandpower_from_psd_ndarray) now print a warning if the PSD contains negative values. See [issue 29](https://github.com/raphaelvallat/yasa/issues/29).
- Upon loading, YASA will now use the [outdated](https://github.com/alexmojaki/outdated) package to check and warn the user if a newer stable version is available.
- YASA now uses the [AntroPy](https://github.com/raphaelvallat/antropy) package to calculate non-linear features in the automatic sleep staging module. Previously, YASA was using [EntroPy](https://github.com/raphaelvallat/entropy), which could not be installed using pip.