Handle toObject in updateAttributes

Since one can call updateAttributes with any kind of properties (as
opposed to save, which uses toObject internally), any objects that
correspond to toObject should be handled as such. This is particularly
the case with List objects, as used by embedsMany.

lib/dao.js

@@ -1175,6 +1175,10 @@ DataAccessObject.prototype.updateAttributes = function updateAttributes(data, cb
             // Convert the properties by type
             inst[key] = data[key];
             typedData[key] = inst[key];
+            if (typeof typedData[key] === 'object' 
+              && typeof typedData[key].toObject === 'function') {
+              typedData[key] = typedData[key].toObject();
+            }
           }
 
           inst._adapter().updateAttributes(model, getIdValue(inst.constructor, inst),