Fix bug in KineticsModel.isIdenticalTo

This method just checks that Tmin and Tmax are equal.
But if they were equal, it used to return False.

Now it returns False if one or other is None, or they're
different. Note, however, that because the Quantity.equals
method defaults to a 1% tolerance, that's 20K difference
needed at 2000K.

rmgpy/kinetics/model.pyx

@@ -230,15 +230,15 @@ cdef class KineticsModel:
         Returns ``True`` if Tmin, Tmax for both objects match.
         Otherwise returns ``False``
         """
-        if self.Tmin is not None and other_kinetics.Tmin is not None and not self.Tmin.equals(other_kinetics.Tmin):
-            return False
+        if self.Tmin is not None and other_kinetics.Tmin is not None and self.Tmin.equals(other_kinetics.Tmin):
+            pass
         elif self.Tmin is None and other_kinetics.Tmin is None:
             pass
         else:
             return False
 
-        if self.Tmax is not None and other_kinetics.Tmax is not None and not self.Tmax.equals(other_kinetics.Tmax):
-            return False
+        if self.Tmax is not None and other_kinetics.Tmax is not None and self.Tmax.equals(other_kinetics.Tmax):
+            pass
         elif self.Tmax is None and other_kinetics.Tmax is None:
             pass
         else: