This reverts commit e3a9ca27b1, reversing
changes made to 3d8bdeb429.
Conflicts:
zipline/gens/tradesimulation.py
The aforementioned change needs a revert because it caused a 'doubling'
of orders, since the portfolio is not updated until after handle_data
is called a second time after an order has been processed.
The flexibility of fill_delay is still desired, but remove for now,
favoring reverting back to existing behavior over trying ot fix the
fill_delay logic.