width and precision in TAP_SCHEMA.columns

[Walter Landry]

Hi Everyone,

Looking at the list of VOTable FIELD attributes

  http://www.ivoa.net/documents/VOTable/20130920/REC-VOTable-1.3-20130920.html#ToC25

they mostly map straight to columns in TAP_SCHEMA.columns.  Two
significant exceptions are width and precision.  Maybe we should add
those?  We can always get it by doing a null query, but it seems like
something that should be in TAP_SCHEMA.columns.

Thanks,
Walter Landry