Modified slide and message to include fields to conform to the new
standard. slide now has an ID and meta field, where ID should be unique to
each slide. This is insured by the accessor helper defined in slideShow
that raises an exception if it encounters more then one slide with the
same id. message now has a datetime field that defaults to None. should
either edit old code to include the datetime as an arg to the constructor
or if no one is supplied to the constructor use current datetime as value
for field. this code has not been tested and will not run right now as the
dds-wp api doesn't supply the required information on slide load. once
that happens we can test this code.