[arty-fishL]

Major code overhaul (the one I've been putting off for ages).

I needed to do this as the code was so confusing, I was getting nothing done. This has made the code much less messy, much safer (less ambiguity, less need to track names in use) and much more professional.

This has probably introduced a bazillion hidden bugs, but I've eradicated the ones I could find. The good thing is I've fixed and updated the error messages and logging, so that helps.

Unfortunately though there are no surface changes, just mega changes under the bonnet.