2014.09.10 MSS Code Factory CFLib 1.11.12376 Attempted correction for setting editing values to nulls

I'm not sure why TZDate doesn't seem to be persisting edits; it could be a
flaw in the higher level code.  But I've re-copied some code from the Date
field (which works) in hopes of fixing whatever is wrong with TZDate.  It's not
that complex a widget at this point.

TZTextEditor isn't fleshed out yet, so it just displays the first line of
the text it's been set to.  I think I'm going to switch that over to a
multi-line text editor and make some layout tweaks (i.e. display 3 lines worth
by default instead of one line.)  But later, later.  For now the other widgets...

When a formatted field editor was being set to an empty value (null), it
wasn't properly clearing the inherited Value attribute of the widget.  It
does that now, so hopefully I'll be able to edit into null values and persist
them.