MAINT: Restore @property decorator
MAINT: Restore @property decorator

This will keep `opens`, `closes`, `early_closes`, etc to the
same pattern.

Scapogo/zipline,quantopian/zipline,bartosh/zipline,enigmampc/catalyst,florentchandelier/zipline,Scapogo/zipline,florentchandelier/zipline,alphaBenj/zipline,alphaBenj/zipline,humdings/zipline,quantopian/zipline,bartosh/zipline,humdings/zipline,enigmampc/catalyst