Refactor for modularization.  No functional change.
Refactor for modularization.  No functional change.

* tools/client-side/svn-graph.pl
  (write_graph_descriptor): New function containing most of the
   remaining logic scattered in the global namespace.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion