failing unittests on 32b linux machine
Just did a fresh install of pandas on a 32bits linux machine (ubuntu), i suppose this is a supported platform.
Running nosetests shows many failures (one example at the  bottom).

numpy 1.6.1
Cython 0.16
pandas from master

A lot of them are related to numpy issue:

``` python
In [11]: values = np.random.randn(100000, 5)

In [12]: values.take(np.arange(10, dtype='int32'))
Out[12]: 
array([-0.49410797, -0.24884862,  0.76527299, -0.96366541, -2.64132367,
        0.21082825, -0.09124413, -0.89438207, -0.16012725,  0.20569685])

In [13]: values.take(np.arange(10, dtype='int64'))
---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
/home/lodagro/projects/pandas/<ipython-input-13-6ad7fa396ff4> in <module>()
----> 1 values.take(np.arange(10, dtype='int64'))

TypeError: array cannot be safely cast to required type

In [14]: 
```

```
======================================================================
ERROR: test_append (pandas.sparse.tests.test_sparse.TestSparseDataFrame)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/lodagro/.virtualenvs/pandas/lib/python2.7/site-packages/pandas-0.8.0.dev_789300e-py2.7-linux-i686.egg/pandas/sparse/tests/test_sparse.py", line 1014, in test_append
    a = self.frame[:5]
  File "/home/lodagro/.virtualenvs/pandas/lib/python2.7/site-packages/pandas-0.8.0.dev_789300e-py2.7-linux-i686.egg/pandas/sparse/frame.py", line 318, in __getitem__
    return self.reindex(date_rng)
  File "/home/lodagro/.virtualenvs/pandas/lib/python2.7/site-packages/pandas-0.8.0.dev_789300e-py2.7-linux-i686.egg/pandas/core/frame.py", line 1916, in reindex
    fill_value, limit)
  File "/home/lodagro/.virtualenvs/pandas/lib/python2.7/site-packages/pandas-0.8.0.dev_789300e-py2.7-linux-i686.egg/pandas/sparse/frame.py", line 511, in _reindex_index
    new = values.take(indexer)
TypeError: array cannot be safely cast to required type
```
