Add the changes made since 2.0 RC 3 to the release notes.
Add the changes made since 2.0 RC 3 to the release notes.

Our final releases always had a list of changes since the last RC
release, but we didn't have that in these release notes. This adds that
section with all the latest commits (that matter).

Reviewed at https://reviews.reviewboard.org/r/5843/

sgallagher/reviewboard,davidt/reviewboard,1tush/reviewboard,reviewboard/reviewboard,1tush/reviewboard,sgallagher/reviewboard,1tush/reviewboard,chipx86/reviewboard,custode/reviewboard,1tush/reviewboard,1tush/reviewboard,brennie/reviewboard,KnowNo/reviewboard,custode/reviewboard,davidt/reviewboard,davidt/reviewboard,reviewboard/reviewboard,KnowNo/reviewboard,reviewboard/reviewboard,1tush/reviewboard,beol/reviewboard,bkochendorfer/reviewboard,chipx86/reviewboard,sgallagher/reviewboard,bkochendorfer/reviewboard,KnowNo/reviewboard,beol/reviewboard,beol/reviewboard,sgallagher/reviewboard,1tush/reviewboard,custode/reviewboard,KnowNo/reviewboard,bkochendorfer/reviewboard,chipx86/reviewboard,1tush/reviewboard,davidt/reviewboard,beol/reviewboard,reviewboard/reviewboard,custode/reviewboard,chipx86/reviewboard,bkochendorfer/reviewboard,brennie/reviewboard,brennie/reviewboard,brennie/reviewboard,1tush/reviewboard