Fixing error.
Four major changes.  Now including the new R+R content for changing the structure of the event messages.  Changed the trace parameterization interface (and the relational scraping layer in general) to accomodate the new structure.  Now correctly handling the case in which a single list item has multiple components, currently only possible for table rows, but could conceivably be a more general-purpose relation finder in future, instead of just a list finder.  Several modifications to accomodate that.  Finally, switched to checking the whole row so far for possible xpath parameters, instead of only the most recent entry into the item so far.  Again, this works better when we have multiple texts in a single list item, since we can regiester interactions with any of them.