Draft release notes are up for 9.3.5

I've committed first-draft release notes into HEAD (only, so far).
As in the past couple of release cycles, I've only created a full
new documentation section for 9.3.5; tomorrow I will copy final text
into the back-branch release-note files, trimming away whatever
does not apply to a given branch.

With respect to the ongoing discussion about pg_upgrade's handling
of datminmxid/relminmxid, I've documented that patch on the assumption
that we don't really want to recommend any manual attempts to accomplish
the same result. See the thread on -bugs for discussion if you care.

Comments, corrections?

regards, tom lane