Efficient rigid offset transformation for deformable meshes

From @unihui, When we set each position for deformable object, this function will be called, m_transformApplied would be set to false, then updatePostTransformData will be called for one time for each getVertexPosion, which leads to much unnecessary calculation and reduces the performance. I think it is very powerful with this transformation matrix, but there might be no need for deformable object, just for rigid body. I can solve it in my branch, but it would make no sense to iMSTK platform, so could you help me to check and fix this issue? void

Mesh::setVertexPosition(const size_t& vertNum, const Vec3d& pos)
{
    m_vertexPositions.at(vertNum) = pos;
    m_dataModified = true;
    m_transformApplied = false;
}