Update the 0.8.24 release notes for all the latest changes.
Review Request #7986 — Created Feb. 21, 2016 and submitted
This covers some commits that were missing from the release notes, and adds notes on the new JSExtension.get_settings().
Built the docs and checked the links.
Tool: PEP8 Style Checker Ignored Files: docs/releasenotes/0.8.24.rst Tool: Pyflakes Ignored Files: docs/releasenotes/0.8.24.rst