Science Pack 3 research prerequisites

[Epic3lite]

This is a simple yet fundamental idea: Make sure that any research which requires the Science Pack 3 needs Battery to be researched. It was kind of annoying to have to go to the wiki to find out what research allows Science Pack 3s to be made.

[bobucles]

A simple and user friendly tweak to the tech tree. Obviously this won't make sense if the science pack materials change, but for now it's a +1.

[ThaPear]

I've made a mod that does what you suggest, check it out.