Fixed #19510 -- Race condition in template loading.

Thanks Kronuz and regebro.
Fixed #17037 -- Added a --all option to diffsettings.
Clarified that constant_time_compare doesn't protect string lengths.
Fixed #18447 -- Made LazyObject unwrap on dict access.

Thanks Roman Gladkov and Zbigniew Siciarz.
Fixed #19456 -- Avoid infinite recursion when tracing LazyObject.__init__.

Thanks blaze33 for the patch.
Fixed #19968 -- Dropped support for PostgreSQL < 8.4.
Update versions and links to source tarballs.
Fixed #13260 -- Quoted arguments interpolated in URLs in reverse.
Added warn note to docs about MySQL issues with 0000-00-00 date strings

MySQL accepts 0000-00-00 as a valid date but MySQLdb converts those
values into None. So there will be problems for instance if trying to
transport the data using dumpdata/loaddata.

This patch refs #6642 that has been closed as wontfix since this is a
particular problem of MySQL.
Merge pull request #926 from catalanojuan/adds-dates-containing-zeros-note-to-docs

Added warn note to docs about MySQL issues with 0000-00-00 date strings
Fixed #19327 -- Added handling of double login attempts in admin.

Thanks to Krzysztof Jurewicz for initial patch and
adupin for tests.
small documentation update to outline caveat with SESSION_COOKIE_DOMAIN
Merge pull request #927 from ryanisnan/master

Documentation - Small update to SESSION_COOKIE_DOMAIN documentation
Reworded Mark Pilgrim section in AUTHORS.
Removed the RIP, which seemed callous given today's news of Malcolm's death.
Fixed #20088 -- Changed get_admin_log not to depend on User id field

Before this change, the get_admin_log method would expect User model's
FK to be named `id`. When changing that FK name, admin/index.html
rendering would fail.

This includes:
 * Changed the use of id for the use of pk property.
 * Added a regression test that fails without the patch.

This commit refs #20088.
Fixed #18003 -- Preserved tracebacks when re-raising errors.

Thanks jrothenbuhler for draft patch, Konark Modi for updates.
Merge pull request #931 from catalanojuan/fix-admin-log-dependency-on-user-id-field-20088

Fixed #20088 -- Changed get_admin_log not to depend on User id field
Refs #18586 -- Split out long custom_columns lookup test into multiple tests.
Fixed a python 3.2 syntax error and python 3 warning introduced by 054ce2aa02.
Fixed #16319 -- added SuccessMessageMixin to contrib.messages

Thanks martinogden for the initial patch and d1ffuz0r for tests.