Add missing model resources (#251)

Examples/resources/models/gltf/LICENSE

@@ -1,2 +1,5 @@
 robot.glb model by @Quaternius (https://www.patreon.com/quaternius)
+Licensed under CC0 1.0 Universal (CC0 1.0) - Public Domain Dedication (https://creativecommons.org/publicdomain/zero/1.0/)
+
+greenman.glb, greenman_hat.glb, greenman_sword.glb, greenman_shield.glb models by @iP (https://github.com/ipzaur)
 Licensed under CC0 1.0 Universal (CC0 1.0) - Public Domain Dedication (https://creativecommons.org/publicdomain/zero/1.0/)

Examples/resources/models/obj/cube.obj

@@ -0,0 +1,68 @@
+# reference material
+#mtllib cube.mtl
+
+# object box
+
+# vertex  (XZY)
+v  5.5  0  1.5
+v  8.5  0  1.5
+v  5.5  0  -1.5
+v  8.5  0  -1.5
+v  5.5  3  1.5
+v  8.5  3  1.5
+v  5.5  3  -1.5
+v  8.5  3  -1.5
+
+# normals  (XYZ)
+vn  0  -1  0
+vn  0  1  0
+vn  0  0  1
+vn  1  0  0
+vn  0  0  -1
+vn  -1  0  0
+
+# UVs (XY)
+vt 0.5  0    0 
+vt 1    0    0
+vt 1    0.5  0
+vt 0.5  0.5  0
+vt 0.5  0.5  0
+vt 1    0.5  0
+vt 0.5  1    0
+vt 1    1    0
+vt 0    0.5  0
+vt 1    0.5  0
+vt 1    0    0
+vt 0    0    0
+vt 0    0.5  0
+vt 1    0.5  0
+vt 1    1    0
+vt 0    1    0
+vt 0.5  0    0
+vt 0    0    0
+vt 0    0.5  0
+vt 0.5  0.5  0
+vt 0    0.5  0
+vt 0.5  0.5  0
+vt 0.5  1    0
+vt 0    1    0
+
+# merger 
+g box
+
+# reference material
+#usemtl mat01
+
+# faces
+f 1/9/1 3/10/1 4/11/1 
+f 4/11/1 2/12/1 1/9/1 
+f 5/13/2 6/14/2 8/15/2 
+f 8/15/2 7/16/2 5/13/2 
+f 1/17/6 2/18/6 6/19/6 
+f 6/19/6 5/20/6 1/17/6 
+f 2/6/1 4/5/1 8/7/1 
+f 8/7/1 6/8/1 2/6/1
+f 4/2/3 3/1/3 7/4/3 
+f 7/4/3 8/3/3 4/2/3 
+f 3/22/5 1/21/5 5/24/5 
+f 5/24/5 7/23/5 3/22/5