make compatible with pandas 0.13.1

Author: wholmgren

pvlib/irradiance.py

@@ -10,6 +10,8 @@
 import logging
 pvl_logger = logging.getLogger('pvlib')
 
+import datetime
+
 import numpy as np
 import pandas as pd
 
@@ -167,7 +169,7 @@ def _doy_to_timestamp(doy, epoch='2013-12-31'):
     -------
     pd.Timestamp
     """
-    return pd.Timestamp('2013-12-31') + pd.Timedelta(days=float(doy))
+    return pd.Timestamp('2013-12-31') + datetime.timedelta(days=float(doy))
 
 
 def aoi_projection(surf_tilt, surf_az, sun_zen, sun_az):

setup.py

@@ -32,7 +32,7 @@
 setuptools_kwargs = {
     'zip_safe': False,
     'install_requires': ['numpy >= 1.7.0',
-                         'pandas >= 0.15',
+                         'pandas >= 0.13.1',
                          'pytz',
                          'six',
                          'pyephem',