Cleaning out the Release Notes

Hi all, the release notes (docs/ReleaseNotes.rst) seem like it is
mostly a holdover from 3.2, (the removal of CellSPU is in there

Would anybody be opposed to me cleaning this out so that the actual
changes from 3.3 are the only ones there?

-- Sean Silva


I don't think there's a reason to keep old release notes any longer.


I cleaned them out in r172954.

-- Sean Silva