Quentin Brandon af69eddd1c Add optional timezoneOffset config for appenders
Example:
    log4js.configure({
        appenders: [{type: 'console', timezoneOffset: -540}],
        replaceConsole: true
    });

The expected value is the equivalent of (new Date).getTimezoneOffset()
In this example, -540 is the value for JST.
This allows machines members of world-wide-spread cluster to all report
log time-stamps using the same timezone (or adapt the timezone to a
local different from the system)
2015-03-20 11:51:23 +09:00
..
2014-09-08 12:17:50 +02:00