Time Zone problem with tz_localize
Hi All,

I'm having a issue with tz_localize, maybe is my misunderstanding.

I'm importing a dataframe and I want to se the timezone for central Europe:

So if I use **Eurpe/Rome** I get:

```
In [303]: df.index.tz_localize('Europe/Rome')
Out[303]: 
DatetimeIndex(['2012-12-15 00:00:00+01:00', '2012-12-15 00:15:00+01:00',
               '2012-12-15 00:30:00+01:00', '2012-12-15 00:45:00+01:00',
               '2012-12-15 01:00:00+01:00', '2012-12-15 01:15:00+01:00',
               '2012-12-15 01:30:00+01:00', '2012-12-15 01:45:00+01:00',
               '2012-12-15 02:00:00+01:00', '2012-12-15 02:15:00+01:00',
               ...
               '2015-10-20 21:30:00+02:00', '2015-10-20 21:45:00+02:00',
               '2015-10-20 22:00:00+02:00', '2015-10-20 22:15:00+02:00',
               '2015-10-20 22:30:00+02:00', '2015-10-20 22:45:00+02:00',
               '2015-10-20 23:00:00+02:00', '2015-10-20 23:15:00+02:00',
               '2015-10-20 23:30:00+02:00', '2015-10-20 23:45:00+02:00'],
              dtype='datetime64[ns, Europe/Rome]', name=u'Date Time', length=8064, freq=None)
```

But I dont want to use dst because my timeseries is with no dst so I tried to use **Etc/GMT+1**

```
In [305]: df.index.tz_localize('Etc/GMT+1')
Out[305]: 
DatetimeIndex(['2012-12-15 00:00:00-01:00', '2012-12-15 00:15:00-01:00',
               '2012-12-15 00:30:00-01:00', '2012-12-15 00:45:00-01:00',
               '2012-12-15 01:00:00-01:00', '2012-12-15 01:15:00-01:00',
               '2012-12-15 01:30:00-01:00', '2012-12-15 01:45:00-01:00',
               '2012-12-15 02:00:00-01:00', '2012-12-15 02:15:00-01:00',
               ...
               '2015-10-20 21:30:00-01:00', '2015-10-20 21:45:00-01:00',
               '2015-10-20 22:00:00-01:00', '2015-10-20 22:15:00-01:00',
               '2015-10-20 22:30:00-01:00', '2015-10-20 22:45:00-01:00',
               '2015-10-20 23:00:00-01:00', '2015-10-20 23:15:00-01:00',
               '2015-10-20 23:30:00-01:00', '2015-10-20 23:45:00-01:00'],
              dtype='datetime64[ns, Etc/GMT+1]', name=u'Date Time', length=8064, freq=None)
```

I don't get why now I have -1 in stead of +1.
If I use **Etc/GMT-1**  I get:

```
In [304]: df.index.tz_localize('Etc/GMT-1')
Out[304]: 
DatetimeIndex(['2012-12-15 00:00:00+01:00', '2012-12-15 00:15:00+01:00',
               '2012-12-15 00:30:00+01:00', '2012-12-15 00:45:00+01:00',
               '2012-12-15 01:00:00+01:00', '2012-12-15 01:15:00+01:00',
               '2012-12-15 01:30:00+01:00', '2012-12-15 01:45:00+01:00',
               '2012-12-15 02:00:00+01:00', '2012-12-15 02:15:00+01:00',
               ...
               '2015-10-20 21:30:00+01:00', '2015-10-20 21:45:00+01:00',
               '2015-10-20 22:00:00+01:00', '2015-10-20 22:15:00+01:00',
               '2015-10-20 22:30:00+01:00', '2015-10-20 22:45:00+01:00',
               '2015-10-20 23:00:00+01:00', '2015-10-20 23:15:00+01:00',
               '2015-10-20 23:30:00+01:00', '2015-10-20 23:45:00+01:00'],
              dtype='datetime64[ns, Etc/GMT-1]', name=u'Date Time', length=8064, freq=None)
```

Central Europe should be **Etc/GMT+1** is it rigth?

Tnx
