Small bug fix for Storage Depots

This is just a quick bug fix. The “optimizations” from last week caused an occasional (non fatal) exception when Storage Depots tried to determine the priority of factories to distribute and pickup goods. That should be fixed with this patch.

This update also fixes some instances were the cargo drone was unable to plot a path to a building. This would result in the occasional immediate delivery to or pickup from e.g. the Coffee Roaster.

The changelog for v1.0.16:

• Fix resource pickup issues around several buildings.
• Fix some issues with the target selection for cargo drones.