incompatible with latest pandas

When importing this using pandas 0.24 versions, this error occurs:

```python
---> 26 import odo
27 import pytz
28 from tqdm import tqdm

~/anaconda3/lib/python3.6/site-packages/odo/__init__.py in
27 from .backends.sas import sas7bdat
28 with ignoring(ImportError):
---> 29 from .backends.pandas import pd
30 with ignoring(ImportError):
31 from .backends.bcolz import bcolz

~/anaconda3/lib/python3.6/site-packages/odo/backends/pandas.py in
100
101
--> 102 @convert.register((pd.Timestamp, pd.Timedelta), (pd.tslib.NaTType, type(None)))
103 def convert_null_or_nat_to_nat(n, **kwargs):
104 return pd.NaT

AttributeError: module 'pandas' has no attribute 'tslib'
```

Use odo/backends/pandas.py at line 102 and the reported pandas 0.24 import traceback as entry points. Reproduce the import with pandas 0.24, inspect the failing compatibility reference, and verify that importing odo succeeds without the AttributeError.

Written by the indexing model from the issue text.