Add old Pluto image to the selection of textures

Have newhorizons.asset require all child assets to ensure initialization

data/assets/newhorizons.scene

@@ -177,9 +177,6 @@ asset.onInitialize(function ()
         Position = { 4662120063743.592773, 1263245003503.724854, -955413856565.788086 },
         Rotation = { 0.683224, -0.165934, 0.701234, 0.118073 },
     })
-
-    openspace.setPropertyValue("PlutoTrail.renderable.Enabled", false)
-    openspace.setPropertyValue("PlutoTexture.renderable.Enabled", false)
 end)
 
 asset.onDeinitialize(function ()

data/assets/scene/solarsystem/missions/newhorizons/newhorizons.asset

@@ -1,13 +1,13 @@
-asset.request('./model')
-asset.request('./label')
-asset.request('./fov')
-asset.request('./trail')
+asset.require('./model')
+asset.require('./label')
+asset.require('./fov')
+asset.require('./trail')
 
-asset.request('./pluto')
-asset.request('./charon')
-asset.request('./hydra')
-asset.request('./nix')
-asset.request('./styx')
+asset.require('./pluto')
+asset.require('./charon')
+asset.require('./hydra')
+asset.require('./nix')
+asset.require('./styx')
 
 
 local mission = asset.localResource("newhorizons.mission")

data/assets/scene/solarsystem/missions/newhorizons/pluto.asset

@@ -60,6 +60,7 @@ local Pluto = {
             Segments = 400
         },
         ColorTexturePaths = {
+            textures .. "/pluto.png",
             textures .. "/NH_Pluto_mosaic_16384.png",
             textures .. "/NH_Pluto_mosaic_8192.png",
             textures .. "/pmap_cyl_k201.jpg",