Minor cleaning of legacy files

[Martin Desruisseaux]

The following URL

   https://svn.apache.org/repos/asf/sis/
Contains some directories which are reminiscence of old work (e.g. from 
the time when the project was using SVN). I would like to move the 
following directories to a new "archive" directory:

 * branches
 * data/unclassified
 * sandbox
 * site
 * tags
 * trunk

The other directories would be left unchanged since they still apply to 
the current project. Any comments or objection?

    Martin