Trying again to merge ian into master

See merge request !5

Fixed an issue in ibtracs.py savefig_one_storm in which storms that were too short were causing problems.

This reverts commit 32c5af59.

Updates to how ibtracs.py makes plots based on Hurricane Ian

See merge request !4

Mostly switched nClimGrid-Daily v1-0-0, the official 1991-2020 normals, and common download_nclimgrid.py

Fixed issues with basin_maps at the end of the month (missing last day) and also added Bonnie to known issues in the Atlantic in ibtracs.py

Fixed issues with basin_maps at the end of the month (missing last day) and also added Bonnie to known issues in the Atlantic in ibtracs.py

Switching lanczos_one_time_step.py from mean to sum
map_variance.py is working