Implementation of translation log handler

This patch implements the TranslationHandler which is a LogHandler that
enables translation of the log records before they are logged.

The handler is configured declaratively in the logging.conf as follows:

        [handlers]
        keys = translatedlog, translator

        [handler_translatedlog]
        class = handlers.WatchedFileHandler
        args = ('/var/log/api-localized.log',)
        formatter = context

        [handler_translator]
        class = openstack.common.log.TranslationHandler
        target = translatedlog
        args = ('zh_CN',)

A prototype version included with the initial version of the Message
class is removed.

Change-Id: I77b6b8a6f5b6360a9bb67ec56cdc927fe91597be
Allow the Message class to have non-English default locales

This patch does an initial translation of the msgid (which is in
English) when the Message class is created, just in case the system's
default locale is not English.

Change-Id: I24b3779f55c8a57849f42c72f4104f2aa22640eb
Merge "Implementation of translation log handler"
Merge "Allow the Message class to have non-English default locales"