message: convert euler angles to quaternion
diff: namespace ospray {
  namespace sg {
  +// convert euler angles(in radians) to quaternion
  +inline quaternionf toQuaternion(const vec3f &rotation)
  +{
  + float cy = cos(rotation[2] * 0.5);
  + float sy = sin(rotation[2] * 0.5);
  + float cp = cos(rotation[1] * 0.5);
  + float sp = sin(rotation[1] * 0.5);
  + float cr = cos(rotation[0] * 0.5);
  + float sr = sin(rotation[0] * 0.5);
  +
  + auto w = cr * cp * cy + sr * sp * sy;
  + auto x = sr * cp * cy - cr * sp * sy;
  + auto y = cr * sp * cy + sr * cp * sy;
  + auto z = cr * cp * sy - sr * sp * cy;
  +
  + return quaternionf(w, x, y, z);
  +}
  +
  inline quaternionf getRotationQuaternion(const LinearSpace3f &rot)
  {
  float t = rot.vx[0] + rot.vy[1] + rot.vz[2];
  