re #28 integrate sessions management
re #28 add a service to find the language by id
re #28 add i18n parameters in text tags of templates
re #28 add unit test for the new language service method
re #28 edit base view to automatically set the current locale with the
current seller language
re #28 edit the login view to automatically set the current locale when
the user connects
re #28 edit the user settings view to automatically change the interface
language if the user selected language changed
re #28 add translation files
re #28 fix indentation problem in template
re #28 fix unit test error for get_language_by_id
re #28 fix indentation problem in template
Merge pull request #56 from jean553/fix_28D

Fix 28D - Language integration - Chinese