Fixed #5241 -- Kept active transalation in LocaleMiddleware.process_response.
Fixed #19937 - Typo in class-based views intro.
Implemented persistent database connections.

Thanks Anssi Kääriäinen and Karen Tracey for their inputs.
Fixed tests broken in 2ee21d9.
Fixed #19929 -- Improved error when MySQL doesn't have TZ definitions.

Thanks tomas_00 for the report.
Fixed #16612 -- Improved has_changed detection for localized field values

Thanks Simon Charette for the review.
Fixed #18898 -- Added tests with a fix for ModelMultipleChoiceField