added idle render overlays for d2k and ts buildings
developer cheats by default in Tiberian Sun

as long it is in development
light and fans animation for the construction yard
lights and plugs for the power plant
lights and flags for the GDI barracks
set up the GDI helipad better with overlays
complete the spotlight tower sequences
don't display the overlay before the building is completed
fix Could not load type 'System.Action'

by changing .NET target framework from default 4.0 to 3.5
require body orientation for idle overlays

and don't wait for BuildingComplete to generalize for units
replace WithSpinner → WithIdleOverlay
Merge pull request #3681 from Mailaender/overlays

Added WithIdleOverlay Render Trait