Implement take on PeriodIndex
```
In [5]: rng
Out[5]: 
<class 'pandas.tseries.period.PeriodIndex'>
freq: B
[28-Dec-1999, ..., 02-Jan-2001]
length: 54

In [6]: rng.take(np.random.permutation(len(rng)))
Out[6]: 
Int64Index([521672, 521592, 521572, 521587, 521732, 521712, 521512, 521627,
       521552, 521582, 521717, 521752, 521737, 521777, 521647, 521517,
       521597, 521677, 521722, 521622, 521542, 521652, 521682, 521707,
       521632, 521612, 521577, 521772, 521637, 521547, 521557, 521532,
       521667, 521617, 521747, 521527, 521742, 521562, 521607, 521522,
       521642, 521657, 521537, 521662, 521727, 521692, 521702, 521567,
       521697, 521767, 521757, 521602, 521687, 521762])
```
