Remove bogus Require<>s.
Move RenderSprites and RenderSimple into Mods.RA.
Move BeamRenderable into Mods.RA.
Move ContrailRenderable into Mods.RA.
Move TextRenderable into Mods.RA.
Move VoxelRenderable into Mods.RA.
Add a workaround for the legacy map editor.
Merge pull request #6029 from pchote/gametomods

Move *Renderables and Render* out of Game.