Refresh some of the information on the codebase docs.

Review Request #6863 — Created Jan. 31, 2015 and submitted — Latest diff uploaded

Information

Review Board
master
3c713f6...

Reviewers

This fixes up some of the docs to be a bit more modern and to get rid of
old, misleading information.

The Contributing Patches documentation has been updated to talk about
release branches and pull requests.

URLs have been updated throughout the docs to use HTTPS instead of HTTP
when applicable.

Built the docs. Things looked okay.