Custom Weather: Usage Across Scenarios

[rajadain]

When a scenario is duplicated, it's weather fields should be included in the duplication. This includes the weather_custom field. The duplicated scenario should have the exact same file used for its custom weather.

When deleting a custom weather file, check to see if it is also used in other scenarios. If so, then give the user a list of those scenarios and ask them to delete them before deleting the file.

When successfully deleting a custom weather file, switch back to default weather and save and close the dialog, so as not to leave the user in a state wherein they can "Cancel" after deleting custom weather and still hang on to the previous results.