Initial cut at 3.9.0 release notes.  What did I forget?


git-svn-id: svn://svn.valgrind.org/valgrind/branches/VALGRIND_3_9_BRANCH@13682 a5019735-40e9-0310-863c-91ae7b9d1cf9
Remove duplicate entries for 3.9.0.


git-svn-id: svn://svn.valgrind.org/valgrind/branches/VALGRIND_3_9_BRANCH@13683 a5019735-40e9-0310-863c-91ae7b9d1cf9