ImportURDFSetup: add Wavefront/obj support

ImportURDFSetup: initialize mass/inertia to 1 by default (instead of 0)

Demos3/ImportObjDemo/LoadMeshFromObj.cpp

@@ -0,0 +1,17 @@
+#include "LoadMeshFromObj.h"
+#include"../Wavefront/tiny_obj_loader.h"
+#include "OpenGLWindow/GLInstanceGraphicsShape.h"
+#include <stdio.h> //fopen
+#include "Bullet3Common/b3AlignedObjectArray.h"
+#include <string>
+#include <vector>
+#include "Wavefront2GLInstanceGraphicsShape.h"
+
+GLInstanceGraphicsShape* LoadMeshFromObj(const char* relativeFileName, const char* materialPrefixPath)
+{
+	std::vector<tinyobj::shape_t> shapes;
+	std::string err = tinyobj::LoadObj(shapes, relativeFileName, materialPrefixPath);
+		
+	GLInstanceGraphicsShape* gfxShape = btgCreateGraphicsShapeFromWavefrontObj(shapes);
+	return gfxShape;
+}