Draft of release notes for 10-7

@lamagnifica @mhoeber @explorerleslie Please review. (Leslie - in particular, can you review the bullets that have to do with discussions?) Built version at http://draft-107-release-notes.readthedocs.org/en/latest/10-07-2014.html.
Private is how we've messaged it from the customer perspective. We should use that to sell it. Using divided in the doc is fine, here we can keep private.