VOTable handling for RA,DEC in sexagesimal notation

[mcdittmar]

I believe its because the annotated dmtype is RealQuantity, but if the VOTable contains string columns of RA,DEC in sexagesimal notation, the TABLEDATA handler, I think, attempts to make numeric columns from them, and fails miserably.
TypeError, "The value must be a valid Python or Numpy numeric value"

Not sure what to do about this, but probably should be able to handle this notation in Positional columns.