Upgradeable Buildings mod

upgrade system in regards to how the upgrade chain is defined and buildings are upgraded. As a proof of concept the Barracks have been broken up into a base building that only gives 1 experience point and two building upgrades that give the rest of the experience points that the original Barracks gave. The second part of the mod allows for buildings when constructed to obsolete one or more buildings. For example the forge can be obsoleted when a factory is built.
This mod implements the concept of upgradeable buildings and buildings that when constructed obsolete a building in the Installation. The building upgrade part of the mod works like the unit