Propane Generators Version 2.0!

Added Dual-Fuel Generator and Propane Generator custom items, custom icons, custom sprites.

Wired in all the things to make world item generators correctly become items, retain their settings, and make items correctly re-impose settings onto new world items.

Propane Generators version 1.0!

Adds propane and dual-fuel generators to the world. Generators will spawn with a random level of fuel and condition, as well as a random generator type of gas, propane, or dual-fuel.

Propane and dual-fuel generators (with propane selected) can be refueled with propane tanks.

Dual-fuel generators can be switched between fuel types as a timed action.