PyBullet: allow to update an existing heightfield shape

Also, use flags = p.GEOM_CONCAVE_INTERNAL_EDGE to enable internal edge filtering for heightfield (disabled by default)
See https://github.com/bulletphysics/bullet3/blob/master/examples/pybullet/examples/heightfield.py

examples/ExampleBrowser/OpenGLGuiHelper.cpp

@@ -1496,3 +1496,8 @@ void OpenGLGuiHelper::computeSoftBodyVertices(btCollisionShape* collisionShape,
 		}
 	}
 }
+
+void OpenGLGuiHelper::updateShape(int shapeIndex, float* vertices)
+{
+	m_data->m_glApp->m_renderer->updateShape(shapeIndex, vertices);
+}