More modable tech tree

[Nightinggale]

The issue right now, at least when looking through the decompiled code, techs are a mess, which are spread all over the source code. This means most modders haven't figured out anything related to techs other than adding a modded building to the list of what is granted by a tech and that's about it. The result is that the vanilla techs ends up with a whole lot of buildings and a lot of modded buildings are added to techs, which doesn't really make any logical sense, but it was the best match or "I wanted it to be late game, so I just picked a semi random late game tech".

It would be really nice if we could have a tech class, which contains everything related to the tech in question. The tech tree is then a list of classes. Kind of like how IBuildingConfig ends up as a list of buildings. This tech class then has name, research cost and a list of tech requirements. That should be enough for modders to add new techs. Techtree layout might be an issue, but in worst case a tech can have x,y coordinates.

Allowed buildings can be a public list as this allows adding and removing buildings with ease. Maybe methods for more readable mod code. Being able to access the entire list, modders can reorder the order of icons if needed. Right now that doesn't seem to be an option and icons are always added to the front. I haven't been able to figure out why, but at least I have figured out how to control the order of the modded buildings.

This should be enough to make techs fully modable and modder friendly. However it would be nice to add more features, like a building, which requires two techs (say medicineIII and generic sensors).

Removing buildings from the build menu could also be an option, though I would much rather prefer to unlock new variations of buildings with the proposed new type of rotation.