Fix issue 5816 (cone.nff load failure): repair faulty line in 3D model file (#5817)

* Add missing numeric value

* Remove superfluous intermediate folder

* Add reference image

* Update path to match superfluous "NFF" removal

* Move reference screenshot to subfolder

---------

Co-authored-by: Steve M <praktique-tellypresence@yahoo.com>
Co-authored-by: Kim Kulling <kimkulling@users.noreply.github.com>

test/models/NFF/cone.nff

@@ -1,6 +1,6 @@
 
 #red
-f 1.0 0.0 0.0 0.5 45.2776 0 1 cantfindme.png
+f 1.0 0.0 0.0 0.5 0.5 45.2776 0 1 cantfindme.png
 
 
 tess 4

test/models/NFF/ref/README.md

@@ -0,0 +1,4 @@
+# NFF 3D model reference images
+
+## cone.nff
+![cone.nff](screenshots/cone_nff.png)

test/unit/ImportExport/utNFFImportExport.cpp

@@ -50,7 +50,7 @@ class utNFFImportExport : public AbstractImportExportBase {
 public:
     virtual bool importerTest() {
         Assimp::Importer importer;
-        const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/NFF/NFF/ManyEarthsNotJustOne.nff", 0);
+        const aiScene *scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/NFF/ManyEarthsNotJustOne.nff", 0);
         return nullptr != scene;
     }
 };