browser fixes

[Hugh Hoover <heh>]

I found the problem with the txtmodl classes.  Turns out that the key used
in the CxxTreeAssociation was a Symbol rather than a String, so the compare
failed.. ('String' = #String but #String != 'String').  So I made sure the
compare was done as a symbol in both cases.
  Misc fixes: made all cxx organization classes subclasses of Object rather
than Heaper or XuModel.  They neva shoulda been.
  Fixed directory creation code for fileout.  Now, if you cancel, it cancels
correctly (just stops).

--Hugh