Test failures on 32-bit Linux
Testing 32-bit Manylinux1 wheels for Pandas 0.18.1 gives the following errors:

```
======================================================================
ERROR: test_read_dta12 (pandas.io.tests.test_stata.TestStata)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/venv/local/lib/python2.7/site-packages/pandas/io/tests/test_stata.py", line 244, in test_read_dta12
    parsed_117 = self.read_dta(self.dta21_117)
  File "/venv/local/lib/python2.7/site-packages/pandas/io/tests/test_stata.py", line 86, in read_dta
    return read_stata(file, convert_dates=True)
  File "/venv/local/lib/python2.7/site-packages/pandas/io/stata.py", line 170, in read_stata
    return reader.read()
  File "/venv/local/lib/python2.7/site-packages/pandas/io/stata.py", line 1499, in read
    data = self._insert_strls(data)
  File "/venv/local/lib/python2.7/site-packages/pandas/io/stata.py", line 1595, in _insert_strls
    data.iloc[:, i] = [self.GSO[k] for k in data.iloc[:, i]]
KeyError: 4294967299
======================================================================
FAIL: test_isin (pandas.tseries.tests.test_timedeltas.TestTimedeltaIndex)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/venv/local/lib/python2.7/site-packages/pandas/tseries/tests/test_timedeltas.py", line 1681, in test_isin
    self.assertTrue(result.all())
AssertionError: False is not true
======================================================================
FAIL: test_isin (pandas.tseries.tests.test_timeseries.TestDatetimeIndex)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/venv/local/lib/python2.7/site-packages/pandas/tseries/tests/test_timeseries.py", line 3452, in test_isin
    self.assertTrue(result.all())
AssertionError: False is not true
======================================================================
FAIL: test_isin_with_i8 (pandas.tests.series.test_analytics.TestSeriesAnalytics)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/venv/local/lib/python2.7/site-packages/pandas/tests/series/test_analytics.py", line 1128, in test_isin_with_i8
    assert_series_equal(result, expected)
  File "/venv/local/lib/python2.7/site-packages/pandas/util/testing.py", line 1049, in assert_series_equal
    check_less_precise, obj='{0}'.format(obj))
  File "pandas/src/testing.pyx", line 58, in pandas._testing.assert_almost_equal (pandas/src/testing.c:3887)
  File "pandas/src/testing.pyx", line 147, in pandas._testing.assert_almost_equal (pandas/src/testing.c:2769)
  File "/venv/local/lib/python2.7/site-packages/pandas/util/testing.py", line 915, in raise_assert_detail
    raise AssertionError(msg)
AssertionError: Series are different
Series values are different (40.0 %)
[left]:  [False, False, False, False, False]
[right]: [True, True, False, False, False]
======================================================================
FAIL: test_basic (pandas.tests.test_algos.TestIsin)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/venv/local/lib/python2.7/site-packages/pandas/tests/test_algos.py", line 371, in test_basic
    tm.assert_numpy_array_equal(result, expected)
  File "/venv/local/lib/python2.7/site-packages/pandas/util/testing.py", line 957, in assert_numpy_array_equal
    raise_assert_detail(obj, msg, left, right)
  File "/venv/local/lib/python2.7/site-packages/pandas/util/testing.py", line 915, in raise_assert_detail
    raise AssertionError(msg)
AssertionError: numpy array are different
numpy array values are different (33.33333 %)
[left]:  [False, False, False]
[right]: [True, False, False]
======================================================================
FAIL: test_drop_level_nonunique_datetime (pandas.tests.test_multilevel.TestMultiLevel)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/venv/local/lib/python2.7/site-packages/pandas/tests/test_multilevel.py", line 1978, in test_drop_level_nonunique_datetime
    assert_frame_equal(result, expected)
  File "/venv/local/lib/python2.7/site-packages/pandas/util/testing.py", line 1119, in assert_frame_equal
    '{0}, {1}'.format(right.shape[0], right.index))
  File "/venv/local/lib/python2.7/site-packages/pandas/util/testing.py", line 915, in raise_assert_detail
    raise AssertionError(msg)
AssertionError: DataFrame are different
DataFrame shape (number of rows) are different
[left]:  5, MultiIndex(levels=[[2, 3, 4, 5], [2016-03-23 14:00:00, 2016-03-23 15:00:00, 2016-03-23 16:00:00, 2016-03-23 17:00:00]],
           labels=[[0, 1, 2, 2, 3], [0, 1, 2, 2, 3]],
           names=[u'id', u'tstamp'])
[right]: 3, MultiIndex(levels=[[2, 3, 4, 5], [2016-03-23 14:00:00, 2016-03-23 15:00:00, 2016-03-23 16:00:00, 2016-03-23 17:00:00]],
           labels=[[0, 1, 3], [0, 1, 3]],
           names=[u'id', u'tstamp'])
```

https://travis-ci.org/MacPython/pandas-wheels/jobs/142424407
