New time_pivot visualization (#3941)

* New time_pivot visualization

* Minor tweaks

* Addressing comments

superset/assets/javascripts/explore/components/Control.jsx

@@ -13,6 +13,7 @@ const propTypes = {
   label: PropTypes.string.isRequired,
   choices: PropTypes.arrayOf(PropTypes.array),
   description: PropTypes.string,
+  tooltipOnClick: PropTypes.func,
   places: PropTypes.number,
   validators: PropTypes.array,
   validationErrors: PropTypes.array,