Adding table column names; also, some unrelated changes to the XSD.
- Adding column names involved changing various johar.idf and johar.gem
  source files in straightforward ways.
- Needed to restructure johar.xsd; the way that I was saying that a
  Command could have Stages or Parameters but not both was (a) clumsy
  and (b) may have restricted the order of attributes.  Now I check in
  the Java code instead.  New version should be equivalent to the original.