Adds request locale auto setup and support for sf 2.3

Hi, thanks for this nice bundle.

I've been working with it in sf 2.3 and found some troubles so I looked in the forks and found some that added sf2.3 support (particularly from @smottt). Also I missed in this package the functionality for automatically setting up the request locale, which @saithis had introduced).
I've merged these and made some fixes so the tests pass.

Please, consider merging.
Thanks and regards,
Javier