Improved error handling pt II

Improved error logging

Performance updates
Smart Farming has been out over a year now, and while I've believed it to be a high performance mod, I have gotten the occasional lag report here n' there.

This past week I've rewritten a good chunk of the mod end to end and I believe to have resolved all of these lag issues that some edge case scenarios may have encountered.

- Of note, the hourly cache update runs about 3-4x faster
- The ongoing performance cost is about 50% faster (where workers check if a zone is valid for sowing)
- For instances of high-population colonies with many huge farms, there may have been cases of unusual lag before. This has been resolved thanks to some helpful reports from Tumbleweed.

- Fixes a circumstance where smart sowing thinks the conditions are impossible in the event you built a path over any one tile of the grow zone (like packed dirt) due to the weakest fertility suddenly becoming 0%.
- Weakest fertility is now shown in the inspector.

New
- By popular request, there is now an "allow harvest" gizmo for grow zones. There is also a mod option to turn this gizmo off if you don't want it and wish to reduce gizmo clutter.

This feature only applies to grow zones. Under the hood, this is version 1.9 of this mod. I'm thinking the v2 update of the mod will extend all these features to hydroponics at long last.

Removed an empty folder that may have caused a 1.3 problem.

Couple of 1.4 bug fixes
- NRE fix when a zone is placed in a new colony
- Food calculations fixed

1.4 support

- Changes to how the mod validates zone data in order to improve its compatibility with other farm-related mods. Many thanks to fellow modder LimeTreeSnake for doing the legwork on this fix.
- Some potential NRE fixes.

German translation added, contributed by Dimos