bug in serial_least_squares. self.KG[-1]==0. should become self.KG[-1]=0.

da/stilt/optimizer.py

@@ -118,9 +118,9 @@ class CO2Optimizer(Optimizer):
             self.KG[:] = PHt / self.HPHR[n]
 
             if 'surface' in self.sitecode[n]: 
-                self.KG[-1]==0.
+                self.KG[-1]=0.
             if 'aircraft' in self.sitecode[n]: 
-                self.KG[:-1]==0.
+                self.KG[:-1]=0.
 
 
             if self.may_localize[n]: