MAINT: Use more exact boolean checks for pandas structures.

To prepare for being compatible with pandas==0.13.0, which is stricter
on boolean checks.

zipline/examples/dual_ema_talib.py

@@ -53,11 +53,11 @@ class DualEMATaLib(TradingAlgorithm):
         self.buy = False
         self.sell = False
 
-        if self.short_ema > self.long_ema and not self.invested:
+        if (self.short_ema > self.long_ema).all() and not self.invested:
             self.order('AAPL', 100)
             self.invested = True
             self.buy = True
-        elif self.short_ema < self.long_ema and self.invested:
+        elif (self.short_ema < self.long_ema).all() and self.invested:
             self.order('AAPL', -100)
             self.invested = False
             self.sell = True

zipline/transforms/batch_transform.py

@@ -381,7 +381,7 @@ class BatchTransform(object):
         else:
             data = self.rolling_panel.get_current()
 
-        if self.supplemental_data:
+        if self.supplemental_data is not None:
             for item in data.items:
                 if item not in self.supplemental_data.items:
                     continue