Sithom

- Added `plot.feature_grid'.
- Added existence check when setting `matplotlib` style in `plot.plot_defaults'.

- Added `place.Point.desc` attribute.
- Added `place.BoundingBox.indices_inside` method.
- Added `place.BoundingBox.pad` method.

- Removed `typeguard` as a requirement.
- Improved colormaps.
- Added `xr.mon_increase` function.

- Added `place.py` with `BoundingBox` and `Point` objects.
- Added `typeguard` as a requirement.
- Added `sithom.plot.lim` with tests to allow percentile limits.