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.
there isn't any such thing as a subtopic. The indented list that you see is the way that a content-specific discussion topic appears in the list of discussion topics. Course-wide topics are not indented, but content-specific ones are (under the name of the section that they're in if I'm remembering correctly). 

The link appears below the title that was given to the post. 
I thought we didn't use "courseware"? I always use course content because I was told that no one calls it that (I know, that's the name of the tab in the UI)