Add config to enable simultaneous non-instant projects.

[bountygiver]

By modifying the CalculateWorkPerHour() for both XComGameState_HeadquartersProjectBuildItem and XComGameState_HeadquartersProjectProvingGround, this should be in a highlander due to it also touching XComGameState_HeadquartersXCom on function GetItemEvents and GetProvingGroundEvents, UIFacility_ProvingGround.UpdateBuildQueue also needs similar update to avoid displaying incorrect information.

[robojumper]

How do you suggest would simultaneous projects be enabled? Global config setting, or a list of things that are allowed to run simultaneously?

[bountygiver]

I think global would be better (for normal builditem), as there's proving grounds for non-simultaneous projects. Also it saves the hassle of handling a non-simultaneous project and a simultaneous project going on at the same time

so maybe don't touch proving grounds one so they can both exist for separate functionality instead of having 2 redundant project types with the same behaviour.