Added languages app
Normalized blog.models.Entry removing the language field
apps.languages.models.Language: code attribute is now index and unique
Languages app load is mandatory, but the languages fields now allow null and are hidden when settings.MULTILANGUAGE is False
Added a redirect to LanguageURLMiddleware if the locale isn't found
Added context processor to append languages list to templates if multi language is active.
Added jingo for jinja2 templates
Not importing language model if not needed
Added url_locale template function
Added url function override if multi language is active. A locale parameter can be specified, if not, will use the current locale or the default one.