AttributeError on import
Just pulled and built 0.9.0 from the master branch. The resulting package yields an error on import:

```
>>> import pandas
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Library/Python/2.7/site-packages/pandas-0.9.0.dev_e98a568_20120916-py2.7-macosx-10.8-x86_64.egg/pandas/__init__.py", line 25, in <module>
    from pandas.core.api import *
  File "/Library/Python/2.7/site-packages/pandas-0.9.0.dev_e98a568_20120916-py2.7-macosx-10.8-x86_64.egg/pandas/core/api.py", line 14, in <module>
    from pandas.core.series import Series, TimeSeries
  File "/Library/Python/2.7/site-packages/pandas-0.9.0.dev_e98a568_20120916-py2.7-macosx-10.8-x86_64.egg/pandas/core/series.py", line 23, in <module>
    from pandas.tseries.index import DatetimeIndex
  File "/Library/Python/2.7/site-packages/pandas-0.9.0.dev_e98a568_20120916-py2.7-macosx-10.8-x86_64.egg/pandas/tseries/index.py", line 10, in <module>
    from pandas.tseries.frequencies import infer_freq, to_offset, get_period_alias
  File "/Library/Python/2.7/site-packages/pandas-0.9.0.dev_e98a568_20120916-py2.7-macosx-10.8-x86_64.egg/pandas/tseries/frequencies.py", line 6, in <module>
    from pandas.tseries.offsets import DateOffset
  File "/Library/Python/2.7/site-packages/pandas-0.9.0.dev_e98a568_20120916-py2.7-macosx-10.8-x86_64.egg/pandas/tseries/offsets.py", line 3, in <module>
    from pandas.tseries.tools import to_datetime
  File "/Library/Python/2.7/site-packages/pandas-0.9.0.dev_e98a568_20120916-py2.7-macosx-10.8-x86_64.egg/pandas/tseries/tools.py", line 262, in <module>
    normalize_date = lib.normalize_date
AttributeError: 'module' object has no attribute 'normalize_date'
```
