Clearer explanation when exception has no message

"No exception supplied" is misleading; actually there is an exception,
but there's no message string.
Fixed #17648 -- Add `for_concrete_model` to `GenericForeignKey`.

Allows a `GenericForeignKey` to reference proxy models. The default
for `for_concrete_model` is `True` to keep backwards compatibility.

Also added the analog `for_concrete_model` kwarg to
`generic_inlineformset_factory` to provide an API at the form level.
Fixed #19607 - prefetch_related crash

Thanks to av@rdf.ru and flarno11@yahoo.de for the report.
Optimisation in prefetch_related_objects
Link to active fork for ODBC backend

It took me quite some time to find if and where the ODBC backend was maintained.
I found (on djangoproject.com):
http://code.google.com/p/django-pyodbc/ (last commit about 3 years ago)
then:
https://github.com/avidal/django-pyodbc avidal fork.
then:
https://github.com/aurorasoftware/django-pyodbc/ aurorasoftware version which has avidal improvements merged.

Avidals version now links to https://github.com/aurorasoftware/django-pyodbc/ which is also the version installed through PIP.
Update link to jQuery Cookie plugin site
Updated my bio
Merge pull request #1209 from tax/master

Updated link to active project for ODBC backend
Merge pull request #1210 from alasdairnicol/jquery_cookie_plugin_link

Updated link to jQuery Cookie plugin site
Fixed #20492 - Removed a broken link in GIS docs.
Fixed a regression in router initialization

Regression was introduced in 6a6bb168b. Thanks Bas Peschier for the
report.
Rotate CSRF token on login
Fixed #14825 -- LocaleMiddleware keeps language

 * LocaleMiddleware stores language into session if it is not present there.
Fixed #20099 -- Eased subclassing of BrokenLinkEmailsMiddleware

Thanks Ram Rachum for the report and the initial patch, and Simon
Charette for the review.
Removed obsolete attribute of DjangoTranslation
Fixed #20455 -- Do not use ngettext for undefined plurals

Using two separate translation strings instead of gettext plural when
there is no reference to the number in the translated string. This
prevents some translations like Russian and Latvian to use the singular
form for 11 or 21.
Fixed some minor translation-related issues
Updated translation catalogs

Updated core/admin/admindocs/comments translation catalogs.
Fixed #11725 -- Made possible to create widget label tag without "for"

Thanks Denis Martinez for the report and initial patch, and
Sergey Kolosov for bringing the patch up to date.
Fixed #20296 -- Allowed SafeData and EscapeData to be lazy