Add test OBJ w/ multiple spaces between elements.

test/models/OBJ/multiple_spaces.obj

@@ -0,0 +1,11 @@
+v   1.0 2.0 3.0   
+v 2.0   3.0 1.0
+v 3.0 1.0   2.0
+v   1.0    2.0    3.0
+
+vt   1.0 2.0 3.0   
+vt 2.0   3.0 1.0
+vt 3.0 1.0   2.0
+vt   1.0    2.0    3.0
+
+f 1  2   3