Issue description
upgrading does not return the materials of the previous level.
Expected behavior
I expected using the built in upgrade feature to be equivalent to deconstructing a building then rebuilding it's replacement. It is not, deconstruction gives back some of the materials used to build the building. When upgrading, %100 the materials of the previous building are removed from existence.
I will be showing how to replicate using unit storage 1 and 2. I know it applies to other upgrades, I believe it applies to all upgrades.
Reproduction steps
Begin with a unit storage 1 and sufficient materials and unity to deconstruct it and build a unit storage 2.
note the current quantity of construction parts 1.
Click on it using the upgrade tool (i) and the unity tool (u).
observe that the number of construction part 1s has not increased where it would have if the storage had been deconstructed then reconstructed at a higher level
Game version
v0.5.1a