Replaced the custom, untested memoize with a similar decorator from Python's
3.2 stdlib. Although some minor performance degradation (see ticket), it is
expected that in the long run lru_cache will outperform memoize once it is
implemented in C.
Thanks to EvilDMP for the report and Baptiste Mispelon for the idea of
replacing memoize with lru_cache.
Language codes for Chinese are zh_Hans (Simplified) and zh_Hant (Traditional).
Added support for browsers that still send the deprecated language codes.
Thanks to Olli Wang for the report.