Add a note about cleaning out unreferenced base text files, as noted by Mattias Engdegår.
Add a note about cleaning out unreferenced base text files, as noted by
Mattias Engdegår.

* notes/wc-ng-design: add note about "svn cleanup"

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