General mod cleanup/modernization

[CubicMelon]

This was my first major mod and boy, is it obvious. A lot of it is messy, inconsistent, and some areas still do things in ways that aren't recommended or have better options (especially with minetest version changes). Its scope has also expanded way more than I first expected (not just machines but also tools, food, armor, etc.)

My next project really should be to comb through every file and try to clean up, make things consistent and better commented, and more efficient in general before I worry about adding anything further.

[CubicMelon]

I'm going to try and make a general "to-do" list when I get the chance to spend some time reviewing the mod.

[CubicMelon]

Probably not going to happen anytime soon unfortunately.