Please merge the ncn-integration branch as of 20 Sep 2023...

[neroden]

...after dealing with any savegame versioning issues.  I don't currently understand the versioning situation well enough to fix the savegame versioning issues.

I've been playing a long-running game with these fixes and they are working fine.

There are two sets of fixes here which are still awaiting integration:
(1) Fixes to attempt to place fisheries in the same ocean as the fishing port they go with.  This is *imperfect* because it doesn't get triggered during cross-connections to pre-existing fisheries, but it's an improvement on what was there before.  It uses the ocean routefinding code I wrote.
(2) Fixes to make sure that industry storage levels don't round down to zero, because when they round down to zero, things break.  This is the one which may need some obnoxious savegame versioning stuff.  Please do the work.  I can't.  But this fix is really absolutely necessary to make the early freight game work.

[jamespetts]

Excellent, thank you for that. I have now had a chance to have a look at this and have added the load/save code and also some initialisation code and code for the advanced settings dialogue. This appears to work. Thank you for your work on this.