Infection prob and Prevalence alternate visibility based on use_within_unit_prevalence.  Fixes #233
Switching off WAL for the moment because it was causing issues with migrations.
Finally have selectors working for #118
Changes in "Use X spread" checkboxes are automatically saved to the DB.  Fixes#118
Fixes Neil's 2 things in #230.
serve fonts locally. Closes issue #82
Renamed wind_direction (migration) and tested max_distance hiding.  Closes #230.
Remove 700 weight so bold will be less bold #82
Change the names of some airborne spread fields to catch up to commit
https://github.com/NAVADMC/SpreadModel/commit/a7ee453f4804998593d65674f03c607c5bc11acf
Now sets busy timeout behavior before switching to WAL mode. The switch to WAL mode can return a database locked error, but setting up the busy retry before switching to WAL allows the program to simply try again. Issue https://github.com/NAVADMC/SpreadModel/issues/225
Merge branch 'master' into Windows