message: wrapped setAuxElements to enable NULL set for auxiliary elements
diff: @@ -772,9 +772,12 @@ cdef class Assembler:
  self.ptr.setNumThreads(t)
  return
  - def setAuxElements(self, AuxElements elems):
  + def setAuxElements(self, AuxElements elems=None):
  '''Set the auxiliary elements'''
  - self.ptr.setAuxElements(elems.ptr)
  + cdef TACSAuxElements *ptr = NULL
  + if elems is not None:
  + ptr = elems.ptr
  + self.ptr.setAuxElements(ptr)
  return
  def createNodeVec(self):
  