- Set delay for tooltips from 1 s to 0.5 s.
- Use exclusively `add_*` for widget creation.
- Remove delay in `ncvmap`.
- Add `analyse_netcdf_xarray`.
- New utility functions `xzip_dim_name_length`, `get_standard_name`,
and `get_units` used in `ncvmethods`.
- Add xarray support for reading files.
- Use f-strings for most string operations.
- New widgets `add_button` and `add_label`.
- Increased number of digits in coordinate formatters.