Added asv benchmark for Period, PeriodIndex

Author: rs2

asv_bench/benchmarks/period.py

@@ -0,0 +1,9 @@
+from pandas import Period, PeriodIndex, date_range
+
+
+class create_period_index_from_date_range(object):
+    goal_time = 0.2
+
+    def time_period_index(self):
+        # Simulate irregular PeriodIndex
+        PeriodIndex(date_range('1985', periods=10000).to_pydatetime(), freq='D')