Description:
------------
I'm running "Olson" Timezone Database Version 2012.8.

Certain timezone transitions seem to be outdated or buggy (wrong abbreviations 
and wrong offsets/dst combinations),

For America/Argentina/San_Luis see 
http://www.timeanddate.com/worldclock/city.html?n=613 and 
http://en.wikipedia.org/wiki/America/Argentina/San_Luis.

I just wanted to get the standard offset 
(http://en.wikipedia.org/wiki/List_of_tz_database_time_zones) for each timezone 
in order to automatically populate a drop drown select box.

For more details / tests see: http://stackoverflow.com/q/13203759/89771.

Test script:
---------------
<?php

function getStandardOffsetFromUTC($timezone)
{
    $timezone = new DateTimeZone($timezone);
    $transitions = array_slice($timezone->getTransitions(), -3);

    foreach (array_reverse($transitions) as $transition)
    {
        if ($transition['isdst'] == 1) // we are interested in standard offsets only
        {
            continue;
        }

        return sprintf('UTC %+03d:%02u', $transition['offset'] / 3600, abs($transition['offset']) % 3600 / 60);
    }

    return false;
}

echo getStandardOffsetFromUTC('America/Argentina/San_Luis') . "\n";
echo getStandardOffsetFromUTC('Antarctica/Casey') . "\n";
echo getStandardOffsetFromUTC('Antarctica/Davis') . "\n";

Expected result:
----------------
UTC -03:00
UTC +11:00
UTC +05:00

Actual result:
--------------
UTC -04:00
UTC +08:00
UTC +07:00