Internationalization

[noyainrain]

Add support for internationalization, i.e. translation and formatting of times/dates, numbers, etc.

[noyainrain]

Users should be able to set language and timezone (attributes of User) and browser settings (navigator.language, Intl.DateTimeFormat.resolvedOptions.timeZone) should only be used as suggestions / default values.

[noyainrain]

i18n toolchain:

• Server: Tornado's built-in i18n (gettext)
• Client: i18next (JSON)
• Translation platform: Transifex

[noyainrain]

Draft:

"""
Types
-----

A *language* is expressed as simplified IETF language code in the form of `{lang}-{region}`, where
both both values consist of two characters, *lang* is lower case and *region* is upper case, e.g.
``en-US``.
"""

class Application:
    """
    .. attribute:: languages

       List of available languages.

       Subclass API: Defaults to ['de-DE', 'en-US'].
    """

    def login(self, code=None, language='en-US'):
    """
    *language* is the selected language of the new user.
    """

class User:
    """
    .. describe:: language

       Selected language from the list of available languages.
    """

[noyainrain]

Depends on #68 .

[noyainrain]

Experimental branch: https://github.com/noyainrain/meetling/tree/i18n