Fixed test .obj file: OBJ Vertex Colors are expected to be floats 0-1

See https://github.com/cnr-isti-vclab/vcglib/blob/master/wrap/io_trimesh/import_obj.h#L326

test/models/OBJ/cube_with_vertexcolors.obj

@@ -1,13 +1,13 @@
 g cube
 
-v  0.0  0.0  0.0  124  110  120
-v  0.0  0.0  1.0  24  0  121
-v  0.0  1.0  0.0  4  0  44
-v  0.0  1.0  1.0  224  0  10
-v  1.0  0.0  0.0  24  200  25
-v  1.0  0.0  1.0  124  10  56
-v  1.0  1.0  0.0  78  10  50
-v  1.0  1.0  1.0  23  0  200
+v  0.0  0.0  0.0  0.48627  0.43137  0.47059
+v  0.0  0.0  1.0  0.09412  0.00000  0.47451
+v  0.0  1.0  0.0  0.01569  0.00000  0.17255
+v  0.0  1.0  1.0  0.87843  0.00000  0.03922
+v  1.0  0.0  0.0  0.09412  0.78431  0.09804
+v  1.0  0.0  1.0  0.48627  0.03922  0.21961
+v  1.0  1.0  0.0  0.30588  0.03922  0.19608
+v  1.0  1.0  1.0  0.09020  0.00000  0.78431
 
 vn 0.0 0.0 1.0
 vn 0.0 0.0 -1.0