pandas.Series does not allow adding timedeltas to series of timestamps with datetime information
xref #10477 

It is possible with numpy, but not with pandas:

```
import numpy as np
import pandas as pd

ts1 = pd.Timestamp('2015-07-01 10:00:00').tz_localize('Europe/London')
ts2 = pd.Timestamp('2015-07-01 11:00:00').tz_localize('Europe/London')
dt = ts2 - ts1

x = np.array([ts1, ts2])
print(x)
dx = np.array([dt, dt])
print(x + dx)

s = pd.Series([ts1, ts2])
print(s)
ds = pd.Series([dt, dt])
print(s + ds)
```

`s + ds` throws an error `ufunc add cannot use operands with types dtype('O') and dtype('<m8[ns]')`
