Adding DateOffset(days=1) produces NonExistentTimeError
```
pd.date_range(pd.Timestamp('2015-1-1', tz='US/Eastern'), pd.Timestamp('2016-1-1', tz='US/Eastern'), freq='H') + pd.DateOffset(days=1)

Traceback (most recent call last):
  File "/home/jeff/.virtualenvs/omnipotent/local/lib/python2.7/site-packages/IPython/core/interactiveshell.py", line 3066, in run_code
    exec(code_obj, self.user_global_ns, self.user_ns)
  File "<ipython-input-21-9574a4185a77>", line 1, in <module>
    pd.date_range(pd.Timestamp('2015-1-1', tz='US/Eastern'), pd.Timestamp('2016-1-1', tz='US/Eastern'), freq='H') + pd.DateOffset(days=1)
  File "/home/jeff/.virtualenvs/omnipotent/local/lib/python2.7/site-packages/pandas/tseries/base.py", line 412, in __add__
    return self._add_delta(other)
  File "/home/jeff/.virtualenvs/omnipotent/local/lib/python2.7/site-packages/pandas/tseries/index.py", line 731, in _add_delta
    new_values = self._add_offset(delta).asi8
  File "/home/jeff/.virtualenvs/omnipotent/local/lib/python2.7/site-packages/pandas/tseries/index.py", line 750, in _add_offset
    result = result.tz_localize(self.tz)
  File "/home/jeff/.virtualenvs/omnipotent/local/lib/python2.7/site-packages/pandas/util/decorators.py", line 89, in wrapper
    return func(*args, **kwargs)
  File "/home/jeff/.virtualenvs/omnipotent/local/lib/python2.7/site-packages/pandas/tseries/index.py", line 1724, in tz_localize
    ambiguous=ambiguous)
  File "pandas/tslib.pyx", line 3781, in pandas.tslib.tz_localize_to_utc (pandas/tslib.c:64980)
NonExistentTimeError: 2015-03-08 02:00:00
```
## INSTALLED VERSIONS

commit: None
python: 2.7.6.final.0
python-bits: 64
OS: Linux
OS-release: 3.13.0-61-generic
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: en_US.UTF-8

pandas: 0.17.1
nose: None
pip: 7.1.0
setuptools: 18.0.1
Cython: None
numpy: 1.10.4
scipy: 0.16.1
statsmodels: None
IPython: 4.0.3
sphinx: None
patsy: None
dateutil: 2.4.2
pytz: 2015.7
blosc: None
bottleneck: None
tables: None
numexpr: None
matplotlib: 1.5.0
openpyxl: None
xlrd: None
xlwt: None
xlsxwriter: None
lxml: None
bs4: 4.4.1
html5lib: None
httplib2: None
apiclient: None
sqlalchemy: 1.0.11
pymysql: None
psycopg2: 2.6.1 (dt dec pq3 ext lo64)
Jinja2: None
