Added info about external SVN links.

git-svn-id: https://svn.microneil.com/svn/PKG-SNF4CGP-NIX/trunk@10 7ef522f6-be79-40a8-b7df-0a85b3383509

ReadMe

 building a CommuniGate module tarball.  Please see the DEVELOPER_NOTES
 file in that directory for instructions on how to build the tarball,
 and other information about the build system.
+
+The SNF4CGP_Developer_Package directory contains external SVN links to
+the following directories:
+
+CodeDweller
+SNFMulti
+SNF4CGP
+SNFClient
+SNF2Check