Update Changelog

Initial pass at updating the changelog, as this hasn't been
done for a few releases. Feel free to add anything I left out, as well
as device specific tweaks and customizations. Also, I have left off
contributor names, but you can add yourself or others where appropriate.

Patchset #2: Remove Extra Space

Change-Id: I1158e8063870e01c67dc09c23f79869863edd08c