Add libtidy to the requirements section in the installation document.

See also bug 772122.
Add a note to the installation documentation about the
CSRF_COOKIE_SECURE setting.

See for more information:

https://docs.djangoproject.com/en/dev/ref/settings/#std:setting-CSRF_COOKIE_SECURE
Merge pull request #1033 from berkerpeksag/csrf-doc

Add a note to the installation documentation about the CSRF_COOKIE_SECURE setting.
Merge pull request #1031 from berkerpeksag/req-update

Add libtidy to the requirements section in the installation document.
bug 863692: Waffle switch "wiki_error_on_delete" to enable error-on-delete in wiki
Merge pull request #1035 from lmorchard/863692-delete-exception-waffle

bug 863692: Waffle switch "wiki_error_on_delete"
bug 831444: remove unused gallery app
Merge pull request #1037 from lmorchard/831444-remove-gallery

bug 831444: remove unused gallery app
progress